Disease burden in patients with restless legs syndrome compared with an apnea and a control cohort

Abstract

The objective of this study was to characterize demographics and disease burden for patients with restless legs syndrome (RLS) compared with an apnea and a control cohort. This retrospective, longitudinal, observational cohort study compared patient demographics, comorbidities, and prescription drug use in a prevalent cohort of RLS patients compared with an apnea and a control cohort. The study examined data from 1 year prior to index date (first ICD-9 diagnosis for RLS during time period 1/1/10 to 7/31/11) through 1 year post-index date in a US claims database. Prevalent RLS patients were identified by at least 2 RLS diagnoses with 2nd diagnosis any time pre- or 1 year post-index date. In a subset of incident RLS patients (no RLS diagnosis in pre-index period) prior sleep disorders and use of sleep aids was also determined. 7,773 prevalent RLS patients were matched 1:1 to apnea and control patients. Mean age of RLS patients was 61.4 years and 73% were female. There were 2,857 incident RLS cases. Due to matching, there was no significant difference in age or sex between cohorts. In the post-index period the prevalence of the most common comorbidities for RLS vs apnea patients was as follows: hypertension (46.9 vs 49.9%), pain (39.8 vs 29.0%), fatigue (17.7 vs 16.7%), anxiety (17.1 vs 8.1%), thyroid disease (16.8 vs 16.5%), depression (14.1 vs 7.4%), anemia (11.0 vs 7.2%), and peripheral neuropathy (10.7 vs 3.2%). Rates of pain, fatigue, anxiety, depression, anemia and peripheral neuropathy were higher (P < 0.001) in RLS patients, while hypertension was higher ( P < 0.0001) in apnea patients. All comorbidities were more common (P < 0.0001) in the RLS cohort than the control cohort. Unspecified insomnia in the incident population affected RLS patients (9.4%) more often ( P < 0.0001) than apnea (4.6%) or control (1.9%) patients. More incident RLS patients required a hypnotic agent during the pre-index period than apnea or control patients (P < 0.0001, RLS vs either). RLS patients used more opioid analgesics, dopamine precursors, benzodiazepines, dopamine agonists, anti-inflammatory agents, anticonvulsants, antidepressants, and anxiolytics than apnea patients or controls. RLS was associated with hypertension, pain, anxiety, depression, anemia, and peripheral neuropathy, and was correlated with the utilization of several medications to control these conditions. This observational study suggests that unspecified insomnia may be an early symptom of RLS. This study was supported by UCB Pharma.