Patient Dropout from Opioid Substitution Treatment

Opioid Substitution Treatment (OST) is an established treatment for opioid dependence. In New Zealand, OST programs areregulated by the Ministry of Health (2014) and Methadone and Buprenorphine/Naloxone (Suboxone) are the primary medications.Retention on OST is a key indicator for stabilisation of patients with opioid dependence. The purpose of the present researchwas to study dropout rates and identify factors associated with the dropout of patients from OST at the Community Alcohol andDrug Service (CADS), Hamilton, from 1st January 2013 to 30th April 2014. A retrospective clinical audit of patients on OSTwas conducted. There were 150 patients on OST in Hamilton under the CADS team during the period of study. Nine patientsdropped out during the study period. Sixty-four patients were randomly selected from the remaining 141 patients who remainedon treatment as a comparison group and for the study sample to be approximately half of the overall population of 150 patients.File review was conducted and potential predictors of dropout were identified. Thirty-five independent variables were selectedand dropout was the dependent variable. The statistical programme SPSS22 was used to analyse the data. Fisher’s exact testwas used and four variables were identified as being associated with dropout: history of intravenous drug use; (Fisher’s exactp = 0.05); history of lifetime imprisonment (Fisher’s exact p =0.05); other medications prescribed, (Fisher’s exact p = 0.04);and opioid type prescribed during the study, i.e. methadone or Suboxone. Patients on Suboxone dropped out more than thoseon methadone, (Fisher’s exact p = 0.00). The overall dropout rate was 6%, which was less than the rates of 15-85% found inprevious studies. The limitations of the study were that it was retrospective and the number of dropouts was small. Furthermore,only patient factors associated with dropout were included in the study and service factors were not included.