Depression management in primary care: an observational study of management changes related to PHQ-9 score for depression monitoring

Background:Since 2009 UK GPs have been incentivised to use depression severity scores to monitor patients' response to treatment after 5-12 weeks of treatment.Aim:To examine the association between the severity scores obtained and follow-up questionnaires to monitor depression and subsequent changes made to the treatment of it.Design and setting:A retrospective cohort study utilising routine primary care records was conducted between April 2009 and March 2011 in 13 general practices recruited from within Hampshire, Wiltshire, and Southampton City primary care trusts.Method:Records were examined of 604 patients who had received a new diagnosis of depression since 1 April 2009, and who had completed the nine-item depression scale of the Patient Health Questionnaire (PHQ-9) at initial diagnosis and a subsequent PHQ-9 within 6 months. The main outcome measure was the odds ratio (OR) for a change in depression management. Change in management was defined as change in antidepressant drug prescription, dose, or referral.Results:Controlling for the effects of potentially confounding factors, patients who showed an inadequate response in score change at the time of second assessment were nearly five times as likely to experience a subsequent change to treatment in comparison with those who showed an adequate response (OR 4.72, 95% confidence interval = 2.83 to 7.86).Conclusion:GPs' decisions to change treatment or to make referrals following a second PHQ-9 appear to be in line with guidance from the National Institute for Health and Clinical Excellence for the monitoring of depression in primary care. Although the present study demonstrates an association between a lack of change in questionnaire scores and treatment changes, the extent to which scores influence choice and whether they are associated with improvements in depression outcomes is an important area for further research