Results and validation of an index to measure health state of patients with depression in automated healthcare databases

Abstract

Background and objective: A Depressive Health State Index (DHSI) based on 29 parameters routinely collected in an automated healthcare database (AHDB) was developed to evaluate the health state of depressive patients, and its evolution. The study objective was to describe and validate this DHSI.Methods: A historical cohort of patients with at least one episode of depression was identified in the Clinical Practice Research Datalink (CPRD). The DHSI was calculated for each episode of depression. Validation was performed by comparing the DHSI between subgroups and using validated definitions of remission (proxy and PHQ-9). Robustness was studied by assessing the impact of modifying parameters of the DHSI.Results: 309,279 episodes of depression were identified in the CPRD between 1 January 2006 and 31 December 2012. Remission was observed in 8% of the patients showing the lower DHSI scores and in 88% of the patients showing the higher DHSI scores. The DHSI was robust to a modification of the most frequent variables and to the removal of rare parameters.Conclusion: The DHSI is specific to depression severity (with remission rates in accordance with the expected variations of the DHSI) and robust. It represents a promising tool for the analysis of AHDBs.

Creation and validation of a linear index to measure the health state of patients with depression in automated healthcare databases

“…We first developed the DHSI (referred as 'weighted DHSI' in the manuscript) to address the current lack of an indicator that could provide a continuous evaluation L-DHSI scores of the health state of patients with depression from AHDBs [5,6]. In its initial shape, the DHSI was built with the same parameters as used in the present L-DHSI but these parameters were weighted to quantify the respective impact of each parameter on the depressive health state beyond its polarity.…”

“…The detailed methods used to create the DHSI, and initial results and validation have been published previously by the same research group [5,6].…”

“…For this study, the same dataset and the same population as for the weighted DHSI was used [5,6]. Patients with at least one depressive episode during the study period (1 January 2006-31 December 2012) were included.…”

“…The L-DHSI is a score comprised of the same 29 different parameters (i.e. existing variables or derived from existing variables) as considered for the initial DHSI (Table 1) [5,6]. These parameters were defined and selected by a group of four clinical and methodological experts among the variables available in the CPRD.…”

“…Weights were attributed to the selected variables by expert inputs based on the different impact that the variables were thought to have on patient's health state. Parameters and weights were defined and attributed by a group of four experts, and a previous publication has shown that this DHSI is robust to individual parameter modifications and specific of depression severity [6].…”