Longitudinal evaluation of health care utilization and costs during the first three years after a new diagnosis of fibromyalgia

OBJECTIVE

To evaluate health care resource utilization and costs 1 year before and 3 years after a fibromyalgia (FM) diagnosis.

METHODS

This retrospective cohort analysis used claims from Humana to identify newly diagnosed FM patients ≥18 years of age based on ≥2 medical claims for ICD-9 CM code 729.1 and 729.0 between June 1, 2002 and March 1, 2005. Prevalence of comorbidities, as well as utilization and costs of pharmacotherapy and health care services were examined for 12 months preceding (pre-diagnosis) and 36 months following (post-diagnosis) the date of first FM diagnosis. These periods were subdivided into 6-month blocks to better observe patterns of change.

RESULTS

We identified 2613 FM patients who had a mean age at diagnosis of 58.5 ± 15.3 years and a mean Charlson Comorbidity Index of 0.48 ± 1.05. Of those, 73% were female. The use and costs of pain-related medications rose from pre-diagnosis and remained stable after the 6-month post-diagnosis period, while the use of non-pain-related medications steadily rose from pre-diagnosis to 3 years post-diagnosis. This increase was concomitant with an increase in the presence of conditions that may account for higher resource utilization. The use of recommended FM therapies (i.e., antidepressants and anticonvulsants) increased post-diagnosis but remained less common than other pain-related therapies. Total resource utilization and costs increased during the period up to 6 months after diagnosis. This increase was followed by a decline (7-12 months post-diagnosis), and plateau, with an increase during the final 6 months of the study period. Total mean per patient costs were $3481 for the 6-month post-diagnosis period, and $3588 for the final 6 months. Limitations include potential errors in coding and recording, and an inability of claims analyses to determine causality between resource utilization and the specific diagnosis of interest.

CONCLUSIONS

An FM diagnosis was associated with increased utilization and pain-related medication cost up to the first 6 months post-diagnosis followed by stabilization over 3 years post-diagnosis. Less use of recommended therapies relative to other therapies suggests that further dissemination of treatment guidelines is needed. An increase in non-pain medications over the observation period accounted for the majority of pharmacy costs. These pharmacy costs may be related to an increasing prevalence of comorbid conditions.