To evaluate costs and effectiveness of ambulatory care provided by specialists, nonspecialists (general internists), and both specialists and nonspecialists (co-care) to patients with knee osteoarthritis (OA) and/or chronic low back pain (LBP).
We studied Veterans Health Administration (VHA) outpatients from the Veterans Health Study with LBP and/or OA followed for at least 6 months between August 1993 and December 1995, who completed the Medical Outcomes Study Short Form 36-item (SF-36) functional status questionnaires at both baseline and followup. We obtained costs of VHA outpatient utilization and medications for these patients during the followup period. We compared costs and effectiveness of the ambulatory care provided by specialists, nonspecialists, and co-care. We also compared specialty care with nonspecialty care using an incremental cost effectiveness ratio (ICER) of annualized cost difference divided by annualized SF-36 based Physical Component Summary (PCS) improvement difference. ICER stability was assessed using bootstrap sampling.
Among 398 patients, followed an average of 14 months, 155 received only nonspecialty care, 49 specialty-only care, and 192 co-care. After regression analysis, adjusted for age, disease characteristics, and baseline health status, PCS improvements per year were 1.66 (SD 8.22) for nonspecialty care, 3.48 (SD 7.91) for specialty care, and 0.65 (SD 8.08) for co-care; while costs of care per year were $1099 (SD $1681), $1376 (SD $1503), and $2517 (SD $1644), respectively (all data US dollars). A standardized ICER of $152 per PCS unit indicated specialty care to be cost effective compared with nonspecialty care.
Specialist-only ambulatory care for OA or LBP was associated with improvement in functional status at slightly higher costs compared with nonspecialty care. Co-care, however, was substantially more costly and was associated with little improvement in functional status.