Medically unexplained illness in short- and long-term disability applicants: prevalence and cost of salary reimbursement.

Purpose: Compared to patients with explained illness, patients with medically unexplained illness (MUI) may be at elevated risk of applying for disability. Accordingly, patients with MUI may account for a disproportionate number of disability claims and for a disproportionate percentage of salary reimbursement costs. The study was conducted to determine: (a) The prevalence of MUI among disability insurance claimants; (b) the cost of salary reimbursement; and (c) the impact of psychiatric comorbidity on length and cost of disability.

Method: An insurance database of 26,451 short-term disability (STD) recipients with long-term disability (LTD) coverage was analyzed to determine the prevalence and salary reimbursement costs of MUI. Applicants with medically explained and psychiatric illness were included for comparison.

Results: The prevalence of MUI among STD recipients was lower than clinical and community rates. Rates of application and receipt of LTD benefits for MUI were similar to explained illness. When LTD payments were projected to retirement age, costs associated with unexplained back pain and fibromyalgia were comparable to those of explained illness. The length of disability and salary reimbursement costs were greater when comorbid psychiatric illness was present.

Conclusions: Patients with MUI did not account for a disproportionate number of disability claims or amount of the money spent on salary reimbursement. Comorbid psychiatric illness increased the length and cost of disability.