Classification of patients with bipolar disorder using k-means clustering

PLoS One. 2019 Jan 23;14(1):e0210314. doi: 10.1371/journal.pone.0210314. eCollection 2019.

Abstract

Introduction: Bipolar disorder (BD) is a heterogeneous disorder needing personalized and shared decisions. We aimed to empirically develop a cluster-based classification that allocates patients according to their severity for helping clinicians in these processes.

Methods: Naturalistic, cross-sectional, multicenter study. We included 224 subjects with BD (DSM-IV-TR) under outpatient treatment from 4 sites in Spain. We obtained information on socio-demography, clinical course, psychopathology, cognition, functioning, vital signs, anthropometry and lab analysis. Statistical analysis: k-means clustering, comparisons of between-group variables, and expert criteria.

Results and discussion: We obtained 12 profilers from 5 life domains that classified patients in five clusters. The profilers were: Number of hospitalizations and of suicide attempts, comorbid personality disorder, body mass index, metabolic syndrome, the number of comorbid physical illnesses, cognitive functioning, being permanently disabled due to BD, global and leisure time functioning, and patients' perception of their functioning and mental health. We obtained preliminary evidence on the construct validity of the classification: (1) all the profilers behaved correctly, significantly increasing in severity as the severity of the clusters increased, and (2) more severe clusters needed more complex pharmacological treatment.

Conclusions: We propose a new, easy-to-use, cluster-based severity classification for BD that may help clinicians in the processes of personalized medicine and shared decision-making.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bipolar Disorder / classification*
  • Bipolar Disorder / diagnosis
  • Bipolar Disorder / psychology
  • Cluster Analysis
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Precision Medicine
  • Psychometrics
  • Reproducibility of Results
  • Severity of Illness Index
  • Spain

Grants and funding

This research was supported by grant FIS PI11/02493 (PI: Maria Paz Garcia-Portilla) of the Instituto de Salud Carlos III, Spanish Ministry of Economy and Competitiveness and Fondos Europeos de Desarrollo Regional (FEDER). Lorena de la Fuente-Tomás has received a Severo Ochoa grant supported by Principado de Asturias Goberment. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.