title: Predictors of use of pain medications for persistent knee pain after primary Total Knee Arthroplasty: a cohort study using an institutional joint registry.
abstract: BACKGROUND
  To study the use of pain medications for persistent index knee pain and their predictors after primary Total Knee Arthroplasty (TKA).
  
  
  METHODS
  The Mayo Total Joint Registry collects patient-reported data including pain medication use on all patients who undergo TKA. We used data from patients who underwent primary TKA from 1993-2005. We examined whether gender, age (reference, ≤ 60 yrs), body mass index (BMI; reference, <25 kg/m2), comorbidities measured by Deyo-Charlson index (5-point increase), anxiety and depression predicted use of pain medications (non-steroidal anti-inflammatory drugs (NSAIDs) and opioids) 2- and 5-years after primary TKA. Multivariable logistic regression additionally adjusted for operative diagnosis, American Society of Anesthesiologists (ASA) score, implant fixation and distance from the medical center.
  
  
  RESULTS
  7,139 of the 10,957 eligible (65%) at 2-years and 4,234 of 7,404 eligible (57%) completed questionnaires. Significant predictors of NSAIDs use were (Odds ratio (95% confidence interval)): male gender at 2- and 5-years, 0.5 (0.4, 0.6) and 0.6 (0.5, 0.8); age >70-80 years, 0.7 (0.5, 0.9), 0.6 (0.4, 0.8); and depression, 1.4 (1.0, 1.8) and 1.7 (1.1, 2.5). BMI ≥ 40 was associated with NSAIDs use only at 2-years, 1.6 (1.1, 2.5). Significant predictors of opioid pain medication use at 2- and 5-years were: male gender, 0.5 (0.3, 0.9) and 0.4 (0.2, 0.8); age >70-80 years, 0.3 (0.1, 0.6), 0.3 (0.1, 0.8); and anxiety, 3.0 (1.6, 5.7) and 4.0 (1.7, 9.4).
  
  
  CONCLUSIONS
  Female gender and younger age were associated with higher risk of use of NSAIDs and opioids after primary TKA. Depression was associated with higher NSAID use and anxiety with higher opioid pain medication use after primary TKA.
authors.forename: Jasvinder A
authors.initials: JA
authors.lastname: Singh
authors.forename: David G
authors.initials: DG
authors.lastname: Lewallen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000627:therapeutic use; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use; D001007:Anxiety / Q000139:chemically induced; D018771:Arthralgia / Q000209:etiology / Q000517:prevention & control*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D015992:Body Mass Index; D015331:Cohort Studies; D003863:Depression / Q000139:chemically induced; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000187:drug effects* / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012042:Registries / Q000706:statistics & numerical data
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal