title: Concomitant NSAID use during antipsychotic treatment and risk of 2-year relapse - a population-based study of 16,253 incident patients with schizophrenia.
abstract: OBJECTIVE
  Clinical trials have indicated antipsychotic effects of non-steroidal anti-inflammatory drugs (NSAIDs) among incident patients with schizophrenia. We aimed to study, in a population-based setting, whether concomitant use of NSAIDs or paracetamol, changed 2-year relapse risk for schizophrenia.
  
  
  METHODS
  We identified all incident patients with schizophrenia in Denmark diagnosed 1996-2012 initiating antipsychotic treatment within the year after diagnosis. We calculated concomitant treatment intervals for antipsychotic and NSAID or paracetamol use. Hazard rate ratios (HRR) were estimated using Cox regression adjusted for important covariates.
  
  
  METHODS
  2-year relapse, i.e. (re)-hospitalizations with schizophrenia.
  
  
  RESULTS
  Among 16,235 incident patients with schizophrenia using antipsychotics, 1480 (9.1%) used NSAIDs and 767 (4.7%) paracetamol. Concomitant use of NSAIDs was associated with an increased risk of schizophrenia relapse (HRR = 1.21; 95%-CI = 1.11-1.31), particularly associated with acetylsalicylic acid and diclofenac. Concomitant use of paracetamol was not associated with schizophrenia relapse (HRR = 0.97; 95%-CI = 0.87-1.08). Subgroup analyses showed that individuals with somatic comorbidity and NSAID use had an increased relapse-risk, except for individuals with a prior hospital diagnosis for musculoskeletal disease and NSAID use who had a decreased relapse-risk (HRR = 0.82; 95%-CI = 0.71-0.94).
  
  
  CONCLUSIONS
  The increased relapse risk associated with concomitant NSAID use among incident patients with schizophrenia may indicate a potential impact of underlying somatic comorbidity.
authors.affiliation: a Psychosis Research Unit , Aarhus University Hospital , Risskov , Denmark.|b Psychosis Research Unit , Aarhus University Hospital , Risskov , Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Köhler
authors.affiliation: b Psychosis Research Unit , Aarhus University Hospital , Risskov , Denmark.|c National Centre for Register-based Research , Aarhus University , Aarhus , Denmark.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Petersen
authors.affiliation: d Mental Health Centre Copenhagen, Faculty of Health Sciences , University of Copenhagen , Copenhagen , Denmark.
authors.forename: Michael Eriksen
authors.initials: ME
authors.lastname: Benros
authors.affiliation: a Psychosis Research Unit , Aarhus University Hospital , Risskov , Denmark.|b Psychosis Research Unit , Aarhus University Hospital , Risskov , Denmark.|e CIRRAU , Aarhus University , Aarhus , Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Mors
authors.affiliation: c National Centre for Register-based Research , Aarhus University , Aarhus , Denmark.
authors.forename: Christiane
authors.initials: C
authors.lastname: Gasse
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012306:Risk; D012559:Schizophrenia / Q000188:drug therapy* / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D014150:Antipsychotic Agents
keywords: Antipsychotics; non-steroidal anti-inflammatory drugs (NSAIDs); pharmacoepidemiology; relapse; schizophrenia; somatic comorbidity