title: Joint-pain comorbidity, health status, and medication use in hip and knee osteoarthritis: a cross-sectional study.
abstract: OBJECTIVE
  To determine the prevalence of joint-pain comorbidities in individuals with hip or knee osteoarthritis (OA) and to assess the differences in the characteristics of people with and without joint-pain comorbidities.
  
  
  METHODS
  In this cross-sectional study, individuals referred to secondary care for treatment of hip/knee OA completed questionnaires to determine sociodemographic characteristics, disease-related outcomes, and joint-pain comorbidities. Joint-pain comorbidity was defined as pain perceived in a joint, other than the index joint, for more than half of the days in the preceding month. To compare differences in patient- and disease-related characteristics between participants with and without joint-pain comorbidities, we performed analyses of covariance and logistic regression.
  
  
  RESULTS
  A total of 401 individuals, 117 with hip OA and 284 with knee OA, returned the questionnaire (82% response rate); the mean ± SD age was 58 ± 13 years and 58% of the responders were women. Fifty-eight percent of the participants reported symptoms in ≥1 other joint. Participants with joint-pain comorbidities were more likely to be women, less educated, and have more medical comorbidities. Individuals with joint-pain comorbidities reported unfavorable outcomes on pain, functioning, fatigue, distress, and health-related quality of life compared with patients without joint-pain comorbidities (P < 0.001 for all). Moreover, use of nonsteroidal antiinflammatory drugs (P = 0.038), opioids (P = 0.010), and supplements (P = 0.019) was higher in the group with joint-pain comorbidities.
  
  
  CONCLUSIONS
  Our results indicate that individuals with joint-pain comorbidities represent a clinically relevant and large subgroup of people with OA of the knee or hip. We recommend addressing joint-pain comorbidities in both research and clinical practice.
authors.affiliation: Sint Maartenskliniek, Nijmegen, The Netherlands. t.hoogeboom@maartenskliniek.nl
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hoogeboom
authors.forename: Alfons A
authors.initials: AA
authors.lastname: den Broeder
authors.forename: Bart A
authors.initials: BA
authors.lastname: Swierstra
authors.forename: Rob A
authors.initials: RA
authors.lastname: de Bie
authors.forename: Cornelia H M
authors.initials: CH
authors.lastname: van den Ende
mesh_terms: D000368:Aged; D000700:Analgesics / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000704:Analysis of Variance; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D018771:Arthralgia / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D016009:Chi-Square Distribution; D015897:Comorbidity; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D015207:Osteoarthritis, Hip / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D015995:Prevalence; D011788:Quality of Life; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal