title: Clinical complexity and the effectiveness of an intervention for depressed diabetes patients.
abstract: OBJECTIVE
  In a trial completed in 2010, US patients with diabetes and depression were randomized to usual care or telephone cognitive behavioural therapy that emphasized physical activity. Twelve-month intervention effects were observed for blood pressure, depression, and pedometer-measured step-counts. This study examined variation in intervention effects across patient subgroups defined by a measure of clinical complexity.
  
  
  METHODS
  Three groups of patients were identified at baseline using the Vector Model of Complexity that recognizes socioeconomic, biological, behavioural, and other determinants of treatment response. Complexity-by-intervention interactions were examined using regression models.
  
  
  RESULTS
  Intervention effects for blood pressure, depression, and step-counts differed across complexity levels (each p < 0.01). Effects on Beck Depression Inventory scores were greater in the low-complexity group (-8.8) than in the medium- (-3.2) or high-complexity groups (-2.7). Physical activity effects also were greatest in the low-complexity group (increase of 1498 steps per day). In contrast, systolic blood pressure effects were greater among intervention patients with high complexity (-8.5 mmHg).
  
  
  CONCLUSIONS
  This intervention had varying impacts on physical and mental health depending on patients' clinical complexity. Physical activity and depressive symptom gains may be more likely among less complex patients, although more complex patients may achieve cardiovascular benefits through decreased blood pressures.
authors.affiliation: Ann Arbor VA Healthcare System, HSR&D Center for Clinical Management Research, Ann Arbor, MI, USA. jpiette@umich.edu
authors.forename: John D
authors.initials: JD
authors.lastname: Piette
authors.forename: Marcia
authors.initials: M
authors.lastname: Valenstein
authors.forename: Joseph
authors.initials: J
authors.lastname: Himle
authors.forename: Sonia
authors.initials: S
authors.lastname: Duffy
authors.forename: Trissa
authors.initials: T
authors.lastname: Torres
authors.forename: Mark
authors.initials: M
authors.lastname: Vogel
authors.forename: Caroline
authors.initials: C
authors.lastname: Richardson
mesh_terms: D000368:Aged; D015928:Cognitive Behavioral Therapy; D003863:Depression / Q000628:therapy*; D003920:Diabetes Mellitus / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011795:Surveys and Questionnaires; D013689:Telephone