Severity of illness and healthcare utilization in chronic fatigue syndrome: Population-based and registry-based samples

Background: Chronic fatigue syndrome (CFS) affects people differently and symptoms and severity of illness fluctuates over time. Few studies have examined healthcare utilization (HU) among CFS patients in primary/tertiary care settings or community-dwelling. We evaluated CFS severity and HU using both population- and registry-based samples.

Methods: Data came from two studies: 2007-2009 CFS Follow-Up Study in GA (GA-T1) and 2008-2010 Registry Pilot Study of CFS. We included cases from the GA-T1 population-based study and the Registry study including referrals by providers and a local support group. Participants were evaluated during a one-day clinical evaluation to identify exclusionary conditions and illness severity was assessed using MFI, SF-36, and CDC Symptom Inventory. Subjects meeting the 1994 research case definition were classified as CFS. Subjects who met the case definition algorithm cutoffs but had exclusionary conditions were classified as CFS with exclusions (CFSX). The studies also collected information on HU and socio-demographics.

Results: The analysis included 227 individuals with CFS and CFSX (78 from Registry and 149 from GA-T1). Exclusionary co-morbidity was more prevalent in Registry than GA-T1 (58.97% vs. 53.02%), and illness severity scores were higher for those in Registry (all p< 0.001) – an additional symptom, 11-point higher in symptom severity score, and 2-point higher in all MFI-20 subscales. Minimally important differences were reached in six of the SF-36 subscales, particularly Role Physical (16-points worse), but not in Role Emotional and Mental Health subscales. There were no significant differences in age, sex, race, and BMI. Registry and GA-T1 cases had equal access to healthcare (i.e., insurance/ healthcare source). Registry cases reported using access more in preceding year - more consultation in general health (23.96 vs. 11.25 times), pain (10.85 vs. 4.76), fatigue (23.96 vs. 11.25), sleep (5.04 vs. 2.05), and cognition (3.63 vs. 1.05), and more healthcare needs but fewer unmet needs.

Conclusions: Provider and support group referral CFS cases had higher levels of severity on dimensions of fatigue, CFS symptoms, and functional impairment but not Role Emotional or Mental Health. Despite increased needs for healthcare, Registry patients had fewer unmet needs, perhaps due to increased utilization. This may explain improved functioning in Role Emotional and Mental Health while illness severity was much worse than CFS cases from the general population. These findings suggest that developing a symptom-targeted educational program focused on screening and monitoring fatigue-associated symptoms may positively affect healthcare utilization and health outcomes.