Meta-analysis: hoarding symptoms associated with poor treatment outcome in obsessive-compulsive disorder

DSM-5 recognizes hoarding disorder as distinct from obsessive-compulsive disorder (OCD), codifying a new consensus. Hoarding disorder was previously classified as a symptom of OCD and patients received treatments designed for OCD. We conducted a meta-analysis to determine whether OCD patients with hoarding symptoms responded differently to traditional OCD treatments compared with OCD patients without hoarding symptoms. An electronic search was conducted for eligible studies in PubMed. A trial was eligible for inclusion if it (1) was a randomized controlled trial, cohort or case-control study; (2) compared treatment response between OCD patients with and those without hoarding symptoms, or examined response to treatment between OCD symptom dimensions (which typically include hoarding) and (3) examined treatment response to pharmacotherapy, behavioral therapy or their combination. Our primary outcome was differential treatment response between OCD patients with and those without hoarding symptoms, expressed as an odds ratio (OR). Twenty-one studies involving 3039 total participants including 304 with hoarding symptoms were included. Patients with OCD and hoarding symptoms were significantly less likely to respond to traditional OCD treatments than OCD patients without hoarding symptoms (OR=0.50 (95% confidence interval 0.42-0.60), z=-7.5, P<0.0001). This finding was consistent across treatment modalities. OCD patients with hoarding symptoms represent a population in need of further treatment research. OCD patients with hoarding symptoms may benefit more from interventions specifically targeting their hoarding symptoms.