title: Mortality of those who attended drug services in Scotland 1996-2006: record-linkage study.
abstract: BACKGROUND
  We examine major causes of death amongst persons in contact with drug-treatment services across Scotland during April 1996-March 2006, hereafter Scottish Drug Misuse Database (SDMD) cohort.
  
  
  METHODS
  Drug-treatment records were linked to national registers of deaths and hepatitis C virus (HCV) diagnoses. For eras 1996/97-2000/01 and 2001/02-2005/06, we calculated cause-specific death-rates and standardised mortality ratios (SMRs) using age-, sex- and calendar-rates of the general Scottish population. Major causes of death were identified by high SMRs (>5 across eras) or rates (>50 per 100,000 person-years in either era), and their time-specific influences characterised by proportional hazards analyses.
  
  
  RESULTS
  The SDMD cohort comprised 69,456 individuals, 350,315 person-years and 2590 deaths. The overall SMR reduced from 6.4 (95% CI: 6.0-6.9) to 4.8 (95% CI: 4.6-5.0) between eras. We identified five major causes of death: drug-related (1383 deaths), homicide (118) and infectious diseases (90) with high SMRs; suicide (269) and digestive system disease (168) with high rates. HCV diagnosis marked individuals with at least double the risk of cause-specific mortality, including adjusted hazard ratio (HR) for no HCV diagnosis of 0.46 (95% CI: 0.41-0.53) for drug-related deaths (DRDs) and 0.15 (95% CI: 0.10-0.22) for death from digestive system disease. Increased DRD risk at older age (>34 years) appeared specific to HCV-diagnosed individuals (interaction: χ₁²=7.7, p=0.01). Alcohol misuse increased HRs: for DRD (1.76, 95% CI: 1.50-2.06), suicide (1.88, 95% CI: 1.35-2.60), deaths from digestive system disease (3.19, 95% CI: 2.21-4.60) and non-major causes (1.87, 95% CI: 1.49-2.35). Stimulant misuse increased suicide risk: adjusted HR 1.91 (95% CI: 1.43-2.54).
  
  
  CONCLUSIONS
  Drug-users in Scotland are exposed to variously increased mortality risks. HCV-diagnosed individuals are particularly vulnerable, and may need additional support.
authors: MRC Biostatistics Unit, Robinson Way, Cambridge CB2 0SR, United Kingdom. Elizabeth.merrall@mrc-bsu.cam.ac.uk
authors: Elizabeth L C
authors: EL
authors: Merrall
authors: Sheila M
authors: SM
authors: Bird
authors: Sharon J
authors: SJ
authors: Hutchinson
mesh_terms: D000367:Age Factors; D000437:Alcoholism / Q000150:complications / Q000401:mortality; D002423:Cause of Death; D000697:Central Nervous System Stimulants / Q000633:toxicity; D015331:Cohort Studies; D004066:Digestive System Diseases / Q000150:complications / Q000401:mortality; D062787:Drug Overdose / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006526:Hepatitis C / Q000150:complications / Q000401:mortality; D006801:Humans; D013287:Illicit Drugs / Q000633:toxicity*; D008297:Male; D008498:Medical Record Linkage; D009026:Mortality; D016016:Proportional Hazards Models; D012042:Registries; D012606:Scotland / Q000453:epidemiology; D016320:Substance Abuse Treatment Centers; D019966:Substance-Related Disorders / Q000150:complications / Q000401:mortality* / Q000523:psychology / Q000628:therapy*; D013405:Suicide
chemical_list: D000697:Central Nervous System Stimulants; D013287:Illicit Drugs