The Edinburgh Addiction Cohort: recruitment and follow-up of a primary care based sample of injection drug users and non drug-injecting controls

Abstract

BackgroundInjection drug use is an important public health problem. Epidemiological understanding of this problem is incomplete as longitudinal studies in the general population are difficult to undertake. In particular little is known about early life risk factors for later drug injection or about the life course of injection once established including the influence of medical and social interventions.MethodsIndividuals thought to be drug injectors were identified through a single primary medical care facility in Edinburgh between 1980 and 2006 and flagged with the General Registry Office. From October 2005 - October 2007, these cases were traced and invited to undergo interview assessment covering early life experience, substance use, health and social histories. Age and sex matched controls for confirmed cases (alive and dead) were later recruited through the same health facility. Controls for living cases completed the same structured interview schedule. Data were also collected on cases and controls through linkage to routine primary care records, death registrations, hospital contact statistics and police and prison records. All interviews were conducted with the knowledge and permission of the current GP.ResultsThe initial cohort size was 814. At start of follow up 227 had died. Of the remaining 587: 20 had no contact details and 5 had embarked from the UK; 40 declined participation; 38 did not respond to invitations; 14 were excluded by their GP on health or social grounds and 22 had their contact details withheld by administrative authorities. 448 were interviewed of whom 16 denied injection and were excluded. Of 191 dead cases with medical records 4 were excluded as their records contained no evidence of injection. 5 interviewed cases died before follow up was concluded though these individuals were counted as "live" cases. 1 control per case (dead and alive) was recruited. Linkage to Scottish Morbidity Records data (available from 1981 onwards) on general acute inpatient and day cases, mental health inpatient and day cases and cancer was provided by Information Services, NHS Scotland, for all cases interviewed and all dead cases. The Scottish Prison Service provided records for 198 (46%) of cases interviewed, 48 cases not interviewed and 34 (18%) of dead cases. For a sub-sample of 100 interviewees a search of the Lothian and Borders police database was made for official criminal records and 94 had criminal records. Data linkage for controls is ongoing.ConclusionsInjecting drug users recruited from a community setting can be successfully followed-up through interviews and record linkage. Information from injecting cases is being analysed in terms of injecting patterns and possible influences on these. Comparisons between cases and controls will allow identification of possibly modifiable early life risk factors for drug injection and will also clarify the burden of disease associated with injection and the influence on this of different health and social interventions.

Early life influences on the risk of injecting drug use: case control study based on the Edinburgh Addiction Cohort

“…These exposures appeared under‐recorded in clinical records, making an analysis including dead cases, using exposure information from records, potentially misleading. We investigated other possible administrative sources of early life exposure information, such as social services records, but accessing these proved unfeasible . Bias may have been introduced through control selection.…”

“…Bias may have been introduced through control selection. An historical sampling frame could not be constructed in order to select a control from the same time as case recruitment . Controls were selected conditional on their attendance at a primary health‐care facility; given the typical population frequency of attendance in primary care, it is likely that most potential controls attended during the recruitment period; however, individuals with poorer health probably attended at a higher frequency and may be over‐represented among our controls.…”

“…The Edinburgh Addiction Cohort has been described elsewhere . Cases were recruited between 1980 and 2006 when they presented in primary care with a history of injection drug use, and were followed‐up from October 2005 to November 2007.…”

“…We attempted to ensure that all causal exposures considered preceded the onset of injecting; mean age of onset was 20 years and no case reported injecting prior to secondary school . For exposures related to care experience, housing stability and family problems, only reports of exposure prior to secondary school were considered.…”

Psychiatric Comorbidity and Personality Structure in Patients with Polyvalent Addiction

“…Macleod et al [11] reported that the first drug injection of their cohort was at the age of 19) and as, furthermore, a large subgroup of addicted patients show symptoms of personality disorders [12], we hypothesized that most patients would (a) fulfill the diagnostic criteria for at least one DSM-IV personality disorder and (b) be located at a borderline level of personality organization (PO) according to Kernberg's model [13]. Also, we hypothesized (c) to find a significant relationship between severity of addiction and severity of personality pathology.…”