A record linkage study of hospital episodes for drug treatment clients in Scotland, 1996–2006

Abstract

Despite drug users’ high mortality rates, their contacts with hospital and psychiatric treatment have received comparatively little quantification. We provide a comprehensive summary and characterisation of the hospital and psychiatric treatment episodes of a national cohort of drug treatment clients during 1996–2006. Drug treatment records were linked to national registers of deaths, hepatitis C virus (HCV) diagnoses and hospital and psychiatric episodes (hereafter hospital episode). Allowing for overdispersion, we calculated hospital episode rates (HERs) by main diagnosis at discharge; standardised hospital episode ratios (SHERs) during 2001/2002 to 2005/2006 only and Cox regression analyses of time-to-hospital-episode. The Scottish Drug Misuse Database (SDMD) cohort comprised 69,457 individuals and 350,317 person-years (pys) with 107,723 hospital episodes by 27,124 individuals: 70,094 hospital episodes occurred during 229,504 pys in 2001/2002 to 2005/2006. The five discharge-diagnoses with highest SHERs were: mental and behavioural disorders 40.3 (95% CI: 38.6–42.1), circulatory system disease 3.7 (3.5–4.0), infectious and parasitic diseases 3.7 (3.4–4.0), diseases of the skin and subcutaneous tissue 3.5 (3.4–3.7), injury, poisoning and other consequences of external causes 3.4 (3.3–3.5). HCV-diagnosed clients were at over twofold greater risk of hospital episode (hazard ratio (HR), for those without diagnosis, 0.41, 95% CI: 0.39–0.43) and alcohol misuse increased risk (HR: 1.69, 95% CI: 1.60–1.80). HERs and SHERs align with SDMD clients’ cause-specific mortality pattern. Interventions for drug treatment clients might incorporate preventive strategies to address the significantly elevated diagnosis-specific SHERs – in particular, dual diagnoses with mental illness.

• Hospital episode
• diagnosis-specific
• standardised rate ratios
• drug misuse

Notes

Notes

1. Respectively: 2469 and 3086 out of 7412 episodes.

2. 3288 out of 6057 episodes.

3. Respectively: 719 and 1239 (984 HCV-specific) out of 3024 episodes.