Low back pain service utilization and costs: association with number of visits of chiropractic manipulation, active care, or manual therapy. A retrospective cohort study

BackgroundFor individuals with low back pain (LBP), in the absence of serious pathology clinical practice guidelines (CPG) recommend a stepped approach to management with first-line emphasis on natural history, self-care, and non-pharmaceutical therapies. For individuals with non-surgical LBP initially contacting a chiropractor (DC), physical therapist (PT), or licensed acupuncturist (LAc), the purpose of this retrospective cohort study was to examine the dose response association between the number of visits of chiropractic manipulative therapy (CMT), active care (AC), manual therapy (MT), or acupuncture, exposure to second- and third-line services, and total episode cost. MethodsA national sample of individuals with a single episode of non-surgical LBP occurring in 2017-2019 was analyzed using episode of care as the unit of analysis. The primary independent variables were initial contact with either a DC, PT, or LAc, and the number of visits of CMT, AC, MT, or acupuncture. Dependent measures included rate and timing of use of 13 types of health care services and total episode cost. Results132,199 continuously insured individuals aged 18 years and older initially contacted 21,336 different DCs, 2,734 PTs and 1,339 LAcs for a single episode of non-surgical LBP. These individuals were associated with $62,185,930 in expenditures. The most common number of visits was 1 to 3 - CMT (48.2% of episodes), AC (29.7%), MT (32.1%), and acupuncture (27.0%). For each service, 1 to 3 visits was associated with the lowest rate of exposure to second- and third-line services although rate differences between visit dose categories were generally not significant or clinically. Episode total cost and duration increased significantly with increasing number of visits. CMT was associated with lowest median total episode cost at each level of visit utilization. ConclusionsFor non-surgical LBP episodes initially contacting a DC, PT or LAc, 1 to 3 visits of CMT, AC, MT, or acupuncture was the most common level of utilization, associated with the lowest exposure to second- and third-line services and lowest total episode cost. Among, CMT, AC, MT, and acupuncture, CMT was associated with the lowest total episode cost at each level of utilization. A higher number of visits of CMT, AC, MT or acupuncture was associated with significantly higher total cost, without meaningful impact on exposure to second- or third-line services. Unmeasured clinical benefits may be associated with higher visit counts and warrants further study.