Economic evaluation of four treatments for low-back pain: results from a randomized controlled trial.

OBJECTIVE We sought to compare total outpatient costs of 4 common treatments for low-back pain (LBP) at 18-months follow-up. METHODS Our work reports on findings from a randomized controlled trial within a large medical group practice treating HMO patients. Patients (n = 681) were assigned to 1 of 4 treatment groups, ie, medical care only (MD), medical care with physical therapy (MDPt), chiropractic care only (DC), or chiropractic care with physical modalities (DCPm). Total outpatient costs, excluding pharmaceuticals, were measured at 18 months. We did not perform a cost-effectiveness analysis because previously published findings showed no clinically meaningful difference in outcomes among the 4 treatment groups. Thirty-seven participants were lost to follow-up at 18 months, leaving a final sample size of n = 654. RESULTS Adjusting for covariates, DC was 51.9% more expensive than MD (P < 0.001), DCPm 3.2% more expensive than DC (P = 0.76), and MDPt 105.8% more expensive than MD (P < 0.001). The adjusted mean outpatient costs per treatment group were 369 US dollars for MD, 560 US dollars for DC, 579 US dollars for DCPm, and 760 US dollars for MDPt. CONCLUSIONS This study is the first randomized trial to show higher costs for chiropractic care without producing better clinical outcomes, but our findings are likely to understate the costs of medical care with or without physical therapy because of the absence of pharmaceutical data. Physical therapy provided in combination with medical care and physical modalities provided in combination with chiropractic care do not appear to be cost-effective strategies for treatment of LBP; they produce higher costs without clinically significant improvements in outcome.