Figure 3.

Estimated treatment effect of receiving complementary and integrative health approaches (CIH) on monthly pain intensity ratings (PIRs) over three years among 306,720 US veterans with chronic musculoskeletal pain. The absolute difference (AD; 95% confidence interval [CI]) represents the absolute difference (95% CIs) in average PIRs between the two CIH exposure groups, estimated using a generalized estimating equation (GEE) normal model. Bars represent upper and lower boundaries of the 95% confidence interval of AD. An AD >0 indicates an unfavorable CIH effect (i.e., increasing pain intensity), whereas an AD <0 indicates a favorable or beneficial CIH effect (i.e., decreasing pain intensity). The conventional method was applied to the original full cohort and included a baseline model (with CIH exposure as the sole predictor) and a covariate-adjusted model (for an array of selected covariates, as described in the Methods). Under the causal method, the Propensity Score (PS)–matching analysis refit the baseline model among the PS-matched subcohort while counting each matched pair as a cluster. The two inverse probability of treatment weighting (IPTW) analyses fit a weighted baseline model in the full cohort, with IPTW in the population (IPTW-P) or IPTW in the treated (IPTW-T) as a weight, respectively. The hybrid analysis fit a weighted baseline model in the PS-matched subcohort with the IPTW-T as a weight while accounting for matching.