Estimating the economic benefits of positive shifts in fibromyalgia severity: an exploratory analysis based on modeling of clinical trial data of pregabalin.

OBJECTIVE

To estimate the annualized differences in direct medical and indirect costs associated with improvement in fibromyalgia (FM) severity among pregabalin-treated patients.

METHODS

Data from three clinical trials of pregabalin in patients with FM were modeled; efficacy results were extrapolated. Mean annual costs (direct and indirect) were assigned based on FM severity levels (mild: $10,219; moderate: $26,217; severe: $42,456). FM severity levels were defined using established cut-points on the Fibromyalgia Impact Questionnaire (FIQ). Mean annualized costs at end-point were estimated for all patients within each cohort and the mean differences in costs were compared using a regression model.

RESULTS

Relative to placebo, there was a significantly higher proportion of subjects with mild FM at end-point with pregabalin 450 mg and a significantly lower proportion of subjects with severe FM. Mean total costs were lower with pregabalin (300 mg, $25,721; 450 mg, $24,103) than placebo ($26,162). The difference in mean annual costs was $2059 lower for pregabalin 450 mg (p = 0.003) and $441 lower for pregabalin 300 mg (p = 0.52). Mean direct medical costs were higher with pregabalin (300 mg, $4962; 450 mg, $4820) than placebo ($4364). The difference in mean annual direct medical costs was significantly higher for pregabalin 450 mg by $456 (p < 0.0001) and by $599 for pregabalin 300 mg (p < 0.0001). Mean indirect costs for pregabalin (300 mg, $20,783; 450 mg, $19,306) were lower than placebo ($21,735). The difference in mean annual indirect costs for pregabalin 450 mg was lower by $2429 (p < 0.0001); pregabalin 300 mg was lower by $951 (p = 0.12).

LIMITATIONS: Use of 13-week end-point data from clinical trials to extrapolate to annual costs and an assumption of continuous therapy over the course of 1 year.

CONCLUSIONS

Improvements in FM severity were associated with overall reductions in cost. Reductions in indirect costs may offset the costs of treatment with pregabalin.