title: Increased risk of acute angle closure in retinitis pigmentosa: a population-based case-control study.
abstract: OBJECTIVE
  To investigate the association between retinitis pigmentosa (RP) and acute angle closure during a 15-year follow-up period.
  
  
  METHODS
  Using the Taiwan Longitudinal Health Insurance Database 2000, we identified 382 RP patients based on the diagnostic code of RP (International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) 362.74) made during 1996-2010, excluding subjects under age of 20 years at diagnosis or subjects undergoing lens extraction before the index date. The control group included 3820 randomly selected non-RP subjects matched with the RP patients in age, gender and the index date of diagnosis. The incidence of acute angle closure during the study period was observed based on an ICD-9-CM code of 365.22. Cochran-Mantel-Haenszel test was used to determine the odds ratio (OR) of having acute angle closure in RP patients.
  
  
  RESULTS
  The mean age at the diagnosis of RP was 51.1 years (standard deviation [SD] 16.7). Acute angle closure occurred in 5 RP patients (1.3%) and in 15 controls (0.4%). The mean age with the acute angle closure was 53.3 years (SD 8.0) in RP patients and 64.6 years (SD 8.4) in controls (P = 0.015). After adjusting for age, gender and comorbid disorders, RP patients had 3.64-fold (95% confidence interval [CI], 1.29-10.25, P<0.001) greater odds of having acute angle closure. After stratification for gender and age, the risk of acute angle closure in RP was higher in patients under age of 60 years (adjusted OR 11.84; 95% CI, 2.84-49.48) and male patients (adjusted OR 19.36; 95% CI, 3.43-109.40) (both P = 0.001).
  
  
  CONCLUSIONS
  RP patients had increased risk of acute angle closure than controls. Contrary to the fact that angle closure disease is more prevalent in elderly females in general population, acute angle closure attack occurred earlier in life and the risk was higher in males among RP patients.
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Ko
authors.affiliation: Division of Hematology and Oncology, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
authors.affiliation: Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: De-Kuang
authors.initials: DK
authors.lastname: Hwang
authors.affiliation: Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D006801:Humans; D007348:Insurance, Health; D007908:Lens, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D012174:Retinitis Pigmentosa / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D012307:Risk Factors; D013624:Taiwan