Effectiveness of electroconvulsive therapy on treatment-resistant depressive disorder: A population-based mirror-image study

Abstract

The clinical effects of electroconvulsive therapy (ECT) in treatment-resistant depressive disorders need to be systemically examined in representative samples. This study aimed to examine whether ECT reduced re-hospitalization within one year after discharge. The authors used the Psychiatric Inpatients Medical Claim Dataset, a subset of a total population health claims database from Taiwan, to include 784 inpatients with treatment-resistant depressive disorders screened for ECT during hospitalization between 2001 and 2011. The same number of comparison subjects was selected by frequency matching on the demographic and clinical characteristics. Using a mirror-image comparison design, we compared group differences in re-hospitalization rate, number of hospital days, number of emergency department visits, and direct medical costs during the 1-year pre- and post-ECT periods. The modifying effects of patients’ characteristics on these outcomes were also explored. The results showed that ECT was associated with a significant decrease in the rate of hospitalizations and emergency department visits over the 1-year follow-up period. However, there were no significant difference in the reduced rate of hospitalizations between ECT and comparison group. Demographic and clinical characteristic had no modifying effect on the odds of psychiatric hospitalization. In conclusions, ECT could reduce the rate of hospitalization and number of emergency department visits in patients with treatment-resistant depressive disorders. However, the study results might be biased by the inherent deficits of mirror-image design.

Introduction

Treatment-resistant depression generally refers to an inadequate response to one or more adequate antidepressant treatments (Fava, 2003). The prevalence of treatment-resistant depression ranges from 30% to 70%, based on the definition of treatment-resistant depression and the selected study populations (Fava, 2003; Nemeroff, 2007). Electroconvulsive therapy (ECT) is one treatment choice for major depressive episode (MDE), especially for those with inadequate response (American Psychiatric Association, 2010; Bauer et al., 2013, 2015; Tess and Smetana, 2009). The worldwide expert consensus is that ECT is an appropriate treatment choice in not only the acute and continuation but also in the maintenance phase of treatment for depressive disorder (Bauer et al., 2013, 2015). ECT is a proven potent treatment for major depression, more effective than drug therapy and other brain stimulation (Slotema et al., 2010; UK ECT Review Group, 2003). MDE remission is faster in patients receiving ECT than in those receiving drug therapy (Spaans et al., 2015). The superior efficacy of ECT in diminishing the severity of depressive symptoms has been proven repeatedly (Ren et al., 2014; Spaans et al., 2015; UK ECT Review Group, 2003).

However, recent surveys show a decrease in the utilization of ECT in the psychiatric practice of several countries (Case et al., 2013; Dauenhauer et al., 2011; Lambe et al., 2014). The reasons for such decline in using ECT include public concern over side effects (Dowman et al., 2005), advancement and increased acceptance of psychopharmacological treatment (Mojtabai, 2009), government and professional regulation (Harris, 2006), and disparity in availability and utilization of medical resources among social groups (Case et al., 2012). More extensive evaluation of the long-term effectiveness and cost of ECT may provide valuable information for health care providers and utilizers to guide the decision making process for treatment choice for MDE (Chakrabarti et al., 2010; Smith et al., 2009; Vallejo-Torres et al., 2015).

In terms of effectiveness, the outcome measures for treatment of MDE are not limited to symptomatology (Zimmerman et al., 2008). Several studies explored the impact of ECT on re-hospitalization among patients with MDE. Some studies suggested that ECT at index episode was associated with decreased psychiatric re-admission rates (Rosen et al., 2016; Slade et al., 2017), while the majorities of studies failed to find such effects (Al-Shehhi et al., 2017; Byrne et al., 2012; Ng et al., 2009; Ng et al., 2012; O'Leary and Lee, 1996; Popiolek et al., 2018; Stoudemire et al., 1994; Tor and Abdin, 2018). It should be noted that most of these studies involved very few patients or did not focus on the effect of ECT. Furthermore, several dimensions of outcome measures, such as frequency of emergency department (ED) visits (Knoth et al., 2010), medical expenditures (Kessler, 2012), and length of stay for inpatient care (Cheng et al., 2007; Zhang et al., 2016) are relevant to the cost and burden of MDE, but seldom examined in relation to ECT (Cohen et al., 2013). Although several treatment guidelines recommend the use of ECT in major depressive disorder as a second-line option, the effectiveness of ECT in treatment-resistant depression has not yet been fully investigated.

The current study aimed to examine whether ECT reduced re-hospitalization within one year after discharge. The study was conducted in a population-based study sample drawn from a nationwide database that included all patients with treatment-resistant depressive disorder who received ECT augmentation and a matched comparison group of treatment-resistant depressive disorder patients who received pharmacotherapy alone. The current study employed a mirror-image study design to examine the changes in various clinical outcome indices one-year before and after the ECT. The outcome indices included psychiatric hospitalization rates, length of psychiatric hospital stays, number of ED visits, and direct medical costs during the pre- and post-treatment periods. In addition, factors affecting the effectiveness of ECT were also examined.