This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Making Better Lives: Patient-Focused Care for Low Back Pain (LBP) (NCT02697435), a randomized na study. The primary outcome is Participants' Level of Low Back Pain-associated Disability as Assessed by Roland Morris Disability Questionnaire (RMDQ).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02697435 |
| Phase | NA |
| Condition | Chronic Low Back Pain, Hip Ostearthritis, Myofascial Pain Syndrome |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 55 |
| Arms in the primary outcome | 2 |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
Older Veterans with chronic low back pain were the intended population. The registry record lists additional conditions, including hip osteoarthritis, myofascial pain syndrome, fibromyalgia, depression, maladaptive coping, lumbar spinal stenosis, insomnia, sacroiliac joint pain, lateral hip and thigh pain, anxiety, dementia, and recent leg length discrepancy. The record does not give detailed eligibility criteria or describe the enrolled participants' characteristics beyond the trial population and outcome groups.
Intervention
Patient-centered care was directed by geriatricians trained to assess and treat 11 conditions that commonly affect chronic low back pain. The approach reflects the trial's view of chronic low back pain as potentially involving contributors beyond the spine itself. The registry record does not provide a more detailed account of the care delivered to individual participants.
Comparator
In the imaging-directed care group, participants could follow their initial imaging with a course of care chosen by them and/or their doctor, or choose not to follow a course. The record does not specify which imaging findings or subsequent care choices occurred for each participant.
Primary question
The primary question was whether patient-centered care would produce a greater reduction in low back pain-associated disability by six months than imaging-directed care. Disability was measured with the Roland Morris Disability Questionnaire (RMDQ), and the primary outcome was the change in score from baseline to six months. The posted group means are -1.29 for patient-centered care and -0.08 for imaging-directed care. The unadjusted recalculation estimates the mean difference as 1.21, with a confidence interval from -1.683 to 4.103. The registry also reports a mixed models analysis with p < 0.05 for superiority. These are different analyses of the trial question and should be read with their methods and reporting limits in mind.
3. Trial Design
The registry describes a randomized, single-masked, parallel-group trial. It lists 55 participants as enrolled and marks the study as completed. The study start date is 2016-04-01, and the primary completion date is 2018-05-31. The record identifies the VA Office of Research and Development as sponsor. The meaning of single masking—specifically, which people were masked—is not reported in the registry record.
The two groups were patient-centered care and imaging-directed care. In the patient-centered group, geriatricians trained to assess and treat 11 conditions commonly affecting chronic low back pain directed care. In the imaging-directed group, participants could choose, with or without their doctor's input, whether and how to pursue care after initial imaging. Thus, the comparator was not described as a single fixed treatment course.
The primary outcome was RMDQ score change from baseline to six months. The outcome description says participants were called monthly for six months, and the brief summary describes baseline and monthly data collection. The posted primary outcome gives a mean and standard deviation for each group. The outcome groups contain 24.0 participants in patient-centered care and 26.0 in imaging-directed care. The record does not explain the difference between the enrollment figure and the numbers contributing to these outcome summaries.
The record does not report the randomization procedure, allocation concealment, trial-specific sample-size justification, or the original design assumptions. It also does not specify the identities of masked parties, the details of the care delivered, adherence to the assigned approach, or the timing and content of all follow-up assessments beyond the description of monthly calls and the six-month primary endpoint. Those omissions limit how fully the conduct of the trial can be reconstructed from the registry entry.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: There was no wash out or run in period.
Overall Study
| Stage | Patient-Centered Care | Imaging-Directed Care |
|---|---|---|
| STARTED | 25 | 30 |
| COMPLETED | 24 | 26 |
| NOT COMPLETED | 1 | 4 |
Reasons for not completing this period:
| Reason | Patient-Centered Care | Imaging-Directed Care |
|---|---|---|
| Withdrawal by Subject | 1 | 0 |
| Physician Decision | 0 | 4 |
Analysis population for the primary outcome, as defined in the registry: All participants were called monthly for 6 months. One main outcome measure was Roland Morris score at 6 months.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Patient-Centered Care | Imaging-Directed Care | Total |
|---|---|---|---|---|
| Participants analysed | 25 | 30 | 55 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 4 | 12 | 16 |
| Age, Categorical: >=65 years | Participants | 21 | 18 | 39 |
| Age, Continuous | years | 71.3 (SD 7.5) | 67.2 (SD 5.5) | 69.1 (SD 6.7) |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 24 | 29 | 53 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 8 | 9 | 17 |
| Race (NIH/OMB): White | Participants | 17 | 20 | 37 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Participants' Level of Low Back Pain-associated Disability as Assessed by Roland Morris Disability Questionnaire (RMDQ), measured over Baseline and 6 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the change in low back pain-associated disability, measured with the Roland Morris Disability Questionnaire. The questionnaire contains 24 yes/no items about interference from back pain with daily activities. Its total score ranges from 0 to 24, with a higher score indicating greater impairment. The trial reports the outcome as the change from baseline to six months rather than as a single follow-up score.
Change scores describe how participants' measured disability differed from their own baseline values over the specified period. A negative change is consistent with a lower score at follow-up than at baseline; a positive change is consistent with a higher score. This direction helps interpret the posted means, but a change score alone does not explain what happened to every participant or why the score changed.
The RMDQ is described in the registry as a well-validated measure of low back pain disability. In general, a structured questionnaire provides a consistent way to measure a specified aspect of health across participants and over time. The endpoint focuses on disability associated with back pain, not on every condition listed in the record, and it is distinct from pain intensity. Although the brief summary also describes collecting pain ratings on a 0-10 Numeric Rating Scale, the primary result analyzed is the RMDQ change. The registry record does not report a threshold for an important change in RMDQ score, so the numerical group means alone do not establish how participants experienced the changes.
7. Results Posted in the Registry
- Imaging-Directed Care: mean -0.08 versus -1.29 on control; difference 1.21 (95% CI -1.68 to 4.10), standardized effect d = 0.24; z-test p = 0.412.
Mean difference: Imaging-Directed Care
95% CI: -1.68 to 4.10
Recalculated from the posted summary statistics
8. Statistical Interpretation
The posted primary outcome means are -1.29 for patient-centered care and -0.08 for imaging-directed care. Because the measure is change from baseline, each negative mean indicates a lower RMDQ score at six months on average, while the imaging-directed group mean is close to zero. These are group averages; they do not describe the range of individual participant responses. The standard deviations are 6.05 and 4.12, respectively, indicating variation around the means within each group.
The unadjusted recalculation gives a mean difference of 1.21, defined as imaging-directed care minus patient-centered care, with a 95% confidence interval from -1.683 to 4.103. With that ordering, a positive estimate means the imaging-directed group had a higher, or less negative, mean change than the patient-centered group. The interval includes zero and spans values in both directions. The recalculated unadjusted p-value is 0.412. Considered on its own, this summary-statistic comparison does not provide a precise estimate that rules out no difference.
The registry separately reports a mixed models analysis, labels it as a superiority analysis, and gives p < 0.05. It does not report the model's estimated difference, confidence interval, or additional model details. The mixed-model result and the simple unadjusted recalculation are not interchangeable: the reported analysis uses a model, while the recalculation compares posted summary statistics without adjustment. The record does not provide enough information to determine the exact reasons for their different p-value reports. Both should therefore be described as reported, without treating the recalculation as a replacement for the registry's analysis.
The word “superiority” in the analysis label identifies the type of statistical question recorded; it does not by itself communicate the size or precision of an effect. The missing model estimate and interval make the magnitude and uncertainty of the sponsor-reported result difficult to assess from the registry entry. The unadjusted interval does convey uncertainty, but it is not a model-based interval and should not be attributed to the mixed-model analysis.
The results should be read as evidence from this completed randomized trial, with limitations in what the registry reports. They do not establish why scores changed, whether changes were important to participants, or how results might apply outside the recorded study population. The record lists 55 enrolled participants, while the primary outcome summaries include 24.0 and 26.0 participants in the respective groups; the reason for this difference is not reported in the registry record. No treatment recommendation follows from these statistical summaries.
9. Statistical Methods Explained
The posted endpoint is continuous: each participant has a numerical RMDQ change score, and the group results are expressed as means with standard deviations. For a continuous outcome, a mean describes the average score in a group, while the standard deviation describes how spread out participant scores are around that average. The mean is a summary, not a description of a typical individual in every respect. The observed standard deviations also show that participant responses were not identical.
What the unadjusted comparison represents
The recalculation compares the two posted group means directly. It uses the patient-centered mean change of -1.29 and the imaging-directed mean change of -0.08 to estimate a mean difference of 1.21, with imaging-directed care minus patient-centered care as the ordering. This is an unadjusted comparison of the summary statistics. It does not account for participant-level covariates, repeated measurements, or other possible features of the original analysis. The recalculated p-value is 0.412, and the recalculated confidence interval extends from -1.683 to 4.103.
An unadjusted comparison is useful as a transparent way to examine the reported group summaries. It is not necessarily the same analysis as the one specified or conducted by investigators. In this trial, the registry reports a mixed models analysis, but does not report its model estimate, confidence interval, model specification, or participant-level data. The recalculation consequently cannot reproduce or audit that model from the registry record.
What a mixed model generally does
In general, a mixed model can account for the fact that observations are related, such as repeated outcome measurements from the same participant, while also estimating group-level patterns. A model may include fixed effects for features of interest and random effects to represent structured variation. The precise model form, included terms, covariance assumptions, and handling of incomplete follow-up matter to the resulting estimate and uncertainty. Those choices are not reported in the registry record, so they should not be inferred for this trial. The registry's designation of “Mixed Models Analysis” identifies a broad method family rather than enough detail to reproduce the analysis.
The trial description mentions baseline and monthly telephone collection, while the primary endpoint is defined as change from baseline to six months. Repeated measurements can be informative, but a model using repeated records may answer a different statistical question from a simple comparison of one change summary per group. Without the model details, it is not possible to say precisely how the reported mixed model used the monthly measurements or what population-level quantity its p-value tests.
How to interpret a p-value
In general, a p-value measures how incompatible the observed data are with a specified statistical null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of a difference. The registry gives p < 0.05 for the mixed-model superiority analysis. The recalculated unadjusted p-value is 0.412. Because the methods differ and the registry omits the model's estimate and specifications, these values should be kept attached to their respective analyses rather than combined or treated as contradictory measurements of a single calculation.
A significance threshold is a decision convention, not a measure of precision. A result that meets a threshold can still have an uncertain magnitude, particularly when the associated estimate and interval are absent. Likewise, a p-value from a simple recalculation does not convey all the information in the group means, standard deviations, or confidence interval. Interpretation should consider the estimated difference, its uncertainty, the measurement scale, the analysis method, and the study's reporting completeness together.
What the confidence interval adds
In general, a confidence interval gives a range of values compatible with the data and the assumptions used to calculate it, at the stated confidence level. The recalculated interval is for the unadjusted mean difference, not the mixed-model estimate. Its inclusion of zero means that this summary-statistic interval is compatible with no mean difference as well as with differences in either direction. Its width conveys uncertainty in the recalculated estimate. The registry does not report a confidence interval for the mixed-model analysis.
The interval is not a range containing a fixed proportion of individual participants' outcomes. It concerns uncertainty about a group contrast. Nor does it account for limitations that are not represented in the calculation, such as missing information about eligibility, follow-up, model choices, or outcome completeness. General statistical interpretation therefore depends on both the numerical interval and the data-generating and analysis details.
Why variability matters
The patient-centered group has a standard deviation of 6.05 and the imaging-directed group has a standard deviation of 4.12. In general, larger variability makes a mean difference harder to estimate precisely for a given amount of data, because participant values are more dispersed. The pooled standard deviation used in the recalculation is 5.136. This is a summary of variability for the unadjusted comparison; it is not a measure of treatment effect and does not capture all potential differences between participants.
Over-dispersion is a general concern when observed outcome variability is greater than a statistical model assumes. If a model underestimates variability, its uncertainty estimates can be too small. The registry does not report a dispersion assessment or enough model detail to determine whether over-dispersion was relevant. For this continuous score, the reported standard deviations describe observed spread, but they do not establish whether a model's variance assumptions were appropriate.
Analysis populations and data completeness
The registry says all participants were called monthly for six months, but does not specify whether every participant completed each call or how incomplete observations were handled. It lists 55 enrolled participants and outcome group sizes of 24.0 and 26.0. The reason these counts differ, the number with complete primary outcome data, and the analysis population used for the mixed model are not reported in the registry record. No imputation method, sensitivity analysis, or per-protocol analysis is described. These are important details because analysis choices and missing observations can affect both estimates and uncertainty.
The registry lists two outcome measures and one analysis, but no secondary outcomes are posted. It does not report whether the analysis accounted for multiple outcomes or multiple comparisons. The existence of a superiority label and a p-value does not reveal the full analysis plan. Without the protocol or a fuller statistical analysis description in the record, the planned versus exploratory status of particular analyses is not established.
10. Confidence Intervals and Precision
Precision concerns how narrowly the data locate an estimated quantity. For the unadjusted mean difference, the recalculated estimate is 1.21, and the 95% confidence interval runs from -1.683 to 4.103. The interval crosses zero and includes both negative and positive differences. In general, this means the summary-statistic data do not pin down the direction of the mean difference with high precision under the calculation's assumptions.
The interval is broad relative to the point estimate and permits a range of possible contrasts. It should not be read as a prediction interval for individual participants or as a guarantee that the true value lies within it. A confidence interval is an uncertainty summary that relies on a statistical method and its assumptions. In this case, it belongs to the unadjusted recalculation based on posted group summaries, not to the registry's mixed models analysis.
The observed standard deviations, 6.05 for patient-centered care and 4.12 for imaging-directed care, show meaningful spread in the recorded change scores. In general, variation among participants and the amount of outcome information contribute to the precision of a group comparison. The registry lists 24.0 and 26.0 participants in the outcome groups. The number enrolled is 55, but the record does not explain the distinction between enrollment and the group counts in the primary results.
The mixed-model result is reported as p < 0.05, but its estimate and confidence interval are not reported in the registry record. That p-value alone does not show how large the model-based contrast was or how tightly it was estimated. The unadjusted confidence interval cannot fill that gap because it comes from a different analysis. Accordingly, precision can be discussed directly for the recalculation, but not fully assessed for the sponsor's reported model result.
11. Planning a Similar Trial: Sample Size
This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 283 | 379 |
| 75% of the observed effect | 503 | 674 |
| 50% of the observed effect | 1,132 | 1,515 |
The sample-size figures are planning illustrations based on the observed effect, not the trial's own original design assumptions. They give participants per arm for 80% power and participants per arm for 90% power. They are not total event counts: the event-count convention applies to time-to-event outcomes, whereas this trial's endpoint is continuous. The registry record does not report the original sample-size justification or its assumptions.
The planning calculation assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers an effect equal to 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. Under those stated assumptions, the listed participant requirements per arm are 283 and 379 for planning at 100% of the observed effect; 503 and 674 for planning at 75% of the observed effect; and 1,132 and 1,515 for planning at 50% of the observed effect. In each pair, the first figure is for 80% power and the second is for 90% power.
In general, the 80% power column describes a design with an 80% chance of detecting the specified effect under the assumed model and threshold if that effect were the true one. The 90% column describes the corresponding design with a 90% chance. These are prospective planning concepts, not statements about what happened in this completed trial. Smaller effects need more participants to detect because they are harder to distinguish from random variation.
This is not observed power. It is a planning exercise constructed from the observed effect and stated assumptions; it does not establish the probability that the completed trial detected a true effect, nor does it validate the trial's design. The illustration also should not be mistaken for the original protocol's sample-size calculation, which is not reported in the registry record.
12. How the Sample Size Is Derived
Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z1−α/2 = 1.960) and the desired power (z1−β = 0.842 for 80% and 1.282 for 90%).
Formula
n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.
Worked calculation for this trial
- Observed difference Δ = 1.210; pooled standard deviation σ = 5.136.
- n = 2 × (1.96 + 0.842)2 × 5.1362 / 1.2102 = 282.8, rounded up to 283 participants per arm for 80% power.
The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).
R code
alpha <- 0.05
z_a <- qnorm(1 - alpha / 2) # two-sided
delta <- 1.21 # observed difference in means
sigma <- 5.13610078269498 # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))
# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")
# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2697435)
n <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n)) # difference in sample means
s2 <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1)) # pooled sample variance
tstat <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))
Output from running the code
100% of observed effect: n per arm = 283 (80% power), 379 (90% power)
75% of observed effect: n per arm = 503 (80% power), 674 (90% power)
50% of observed effect: n per arm = 1,132 (80% power), 1,515 (90% power)
power.t.test: 283.8
Simulated power at n = 283 per arm: 0.799 (20000 replicates)The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.
13. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Mixed Models Analysis | not reported | < 0.050 |
The registry reports the sponsor's analysis as a mixed models analysis, labels the comparison as superiority, and gives p < 0.05. It does not give the model-based effect estimate, confidence interval, model specification, or further details about how the analysis handled repeated measurements or incomplete data. The registry's reported analysis therefore cannot be fully interpreted from the p-value alone.
The recalculation uses the posted group means and standard deviations to make an unadjusted comparison. It estimates a mean difference of 1.21, with a 95% confidence interval from -1.683 to 4.103 and an unadjusted p-value of 0.412. Those numbers do not reproduce the mixed model. A simple summary-statistic comparison and a model-based analysis can differ because they use different statistical procedures and potentially different information or assumptions. The registry record does not report enough detail to explain the difference in the p-values.
The recalculated result should be treated as a secondary descriptive check, not as a replacement for the analysis reported in the registry. The sponsor's analysis is the trial's reported analysis; its missing estimate and interval limit assessment of the size and precision of that result. The registry does not flag a discrepancy between the reported and recalculated analyses, but their differing methods and reported p-values still need to remain clearly distinguished.
14. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures and one reported analysis, but it posts no secondary outcome results. It does not describe a multiplicity adjustment, a hierarchy of outcomes, or a family of hypotheses for which the reported p-value was selected. Whether the analysis plan addressed multiple testing is not reported in the registry record. In general, when several outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase unless the analysis plan accounts for that multiplicity. The record does not establish whether or how that issue applied to this trial.
The outcome description says participants were called monthly for six months, and the primary endpoint is specified as change from baseline to six months. The registry does not state how many participants posted the six-month score, whether every monthly assessment was complete, or how missing assessments were treated. It also does not report an imputation method, sensitivity analyses for missing data, or the assumptions used by the mixed model about incomplete observations. The difference between the 55 enrolled participants and the outcome groups of 24.0 and 26.0 is not explained.
Randomization is reported, but the analysis population is not defined. The registry does not state whether the mixed-model analysis followed an intention-to-treat principle, used only participants with available outcomes, or applied another population definition. It does not report a per-protocol analysis or details on adherence and treatment crossover. These omissions make it difficult to assess whether the analysis retained participants according to randomized assignment or how departures from the assigned care approaches were handled.
The registry does not report interim analyses, stopping rules, or a full statistical analysis plan. Such information should not be inferred from the trial's completed status or its p-value. In general, prespecification helps readers distinguish planned analyses from choices made after observing data, but the registry entry does not provide enough detail to make that distinction for all analytic decisions. The absence of these details does not prove that the procedures were absent; it means they are not reported in the registry record.
15. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Patient-Centered Care | 0 | 25 | 0.0% |
| Imaging-Directed Care | 0 | 30 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Patient-Centered Care | 0 of 25 |
| Imaging-Directed Care | 0 of 30 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Patient-Centered Care | 0 of 25 |
| Imaging-Directed Care | 0 of 30 |
The registry reports zero serious adverse events among 25 participants at risk in the patient-centered care group and zero among 30 participants at risk in the imaging-directed care group. It reports zero deaths in each group. The separate counts at risk are the denominators listed for these safety summaries; they should not be confused with the primary outcome group sizes.
These figures describe the events recorded in the registry for the specified categories. A report of zero serious adverse events does not demonstrate that no harms of any kind occurred, and it does not establish that the approaches have identical safety profiles. The registry also reports zero other adverse events among 25 participants at risk in patient-centered care and zero among 30 at risk in imaging-directed care. No serious adverse event terms are listed.
In general, safety counts are most informative when the event definitions, ascertainment process, follow-up period, and completeness of reporting are clear. The registry does not provide further details on those points in the information. The counts therefore should be read as the recorded safety summaries, not as a comprehensive evaluation of every possible adverse event.
16. What the Result Does, and Does Not, Mean
The primary outcome summaries indicate average RMDQ change of -1.29 in patient-centered care and -0.08 in imaging-directed care from baseline to six months. The unadjusted recalculated contrast is 1.21, imaging-directed minus patient-centered, with a confidence interval from -1.683 to 4.103 and p = 0.412. Those summary statistics are compatible with a range of group differences, including no difference. Separately, the registry reports a mixed-model superiority analysis with p < 0.05, without its estimate or confidence interval.
These results do not support collapsing the two analyses into a single conclusion. The recalculation is an unadjusted comparison of posted summary statistics; the registry analysis is described as a mixed model. Since the model details and effect estimate are not reported, readers cannot determine the model-based magnitude or precision from the registry entry. The recorded p-value indicates a statistical result under that analysis, but it does not convey the size or importance of the difference by itself.
The RMDQ measures disability associated with back pain, not all dimensions of health or every condition listed in the registry. Its score change is an average summary and does not show whether individual participants improved, worsened, or remained similar. The registry does not report a threshold for an important change, so the clinical meaning of the observed group means cannot be determined from the scores alone.
The trial record also does not explain the difference between enrollment of 55 and the outcome group counts, or provide details about missing data and the analysis population. The findings should therefore be understood in the context of the recorded measures, group summaries, and incomplete analysis details. They do not establish how results would generalize to populations beyond the older Veterans described, and they do not provide a basis for medical advice.
17. Why This Trial Matters Statistically
This trial raises a statistical question about how to compare care approaches when chronic low back pain is framed as potentially involving several contributors. The patient-centered approach was directed by geriatricians trained to assess and treat 11 conditions associated with chronic low back pain, while the imaging-directed group could choose whether and how to pursue care following imaging. Because the comparator allowed individual choices, the contrast concerns care strategies as described in the registry, rather than two fully specified and uniform treatment regimens.
The primary endpoint is a change score measured with a structured disability questionnaire. Such endpoints can summarize change over time, but they also require clear handling of baseline values, repeated observations, and incomplete follow-up. The registry mentions monthly telephone calls and a six-month primary outcome, then reports a mixed models analysis without enough detail to assess how those measurements entered the model. This makes transparent reporting of the estimate and its uncertainty especially important.
The difference between the reported mixed-model p-value and the unadjusted recalculation illustrates why a statistical result should be read with its method. The recalculation gives a point estimate and interval that describe the unadjusted group-summary contrast; the registry gives a p-value for a model-based analysis but no corresponding estimate or interval. Neither should be presented as if it posted all the information the other lacks.
Finally, the record reports 55 enrolled participants, while the primary outcome groups include 24.0 and 26.0 participants. Without an explanation of this difference or a detailed account of the analysis population, readers cannot fully assess outcome completeness. These reporting gaps do not settle the substantive question, but they shape how precisely the trial's statistical evidence can be interpreted.
18. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record leaves several trial-specific details unreported. It does not explain why the enrollment figure of 55 differs from the primary outcome group counts of 24.0 and 26.0, or state how many participants contributed complete six-month outcomes. The description of monthly telephone calls does not establish that every scheduled measurement was obtained.
The mixed models analysis is reported only by method label and p-value. The model estimate, confidence interval, model terms, covariance structure, treatment of missing data, and analysis population are not reported in the registry record. As a result, the sponsor-reported result cannot be reproduced or fully assessed from the posted information. The unadjusted recalculation is not a substitute for those missing details.
The record identifies the trial as single-masked but does not say who was masked. It does not report the randomization procedure or allocation concealment. It also does not give detailed eligibility criteria, baseline participant characteristics, adherence, or the actual care choices made in the imaging-directed group. This is particularly relevant because that group could follow a chosen course or choose not to follow one.
The registry does not report the original sample-size calculation, interim analyses, stopping rules, or full statistical analysis plan. It lists two outcome measures but posts no secondary results and does not describe multiplicity procedures. The primary endpoint is defined as a change score, but no threshold for an important change is given. These reporting limits constrain conclusions about precision, completeness, and generalizability; they should not be mistaken for proof that an unreported procedure was not conducted.
19. Related Tutorials
20. Related Statistical Calculators
21. Sources
- ClinicalTrials.gov: Making Better Lives: Patient-Focused Care for Low Back Pain (LBP) — NCT02697435.
- Registry record last updated 2019-08-19; status last verified 2019-07.
- Results first posted 2019-08-19.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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22. Record Summary
NCT02697435 is a completed randomized, single-masked, parallel-group trial sponsored by the VA Office of Research and Development. It enrolled 55 participants and compared patient-centered care with imaging-directed care for older Veterans with chronic low back pain.
The primary outcome was change in RMDQ disability score from baseline to six months. The posted means were -1.29 for patient-centered care and -0.08 for imaging-directed care. An unadjusted recalculation estimated a mean difference of 1.21, with a confidence interval from -1.683 to 4.103 and p = 0.412. The registry separately reports a mixed models superiority analysis with p < 0.05, but does not report its estimate or confidence interval.
The registry records zero serious adverse events and zero deaths in both groups. Details on the original sample-size justification, analysis population, missing-data handling, and several model specifications are not reported in the registry record.