Methods:Using workplace survey data for 2 large employers’ healthcare claims (2004-2006), patient selection criteria considered depression diagnosis and antidepressant claims history. Employed respondents working in the past month were categorized by Medication Possession Ratio into compliance groups by quartiles; bottom/top quartiles were defined as compliant/non-compliant. Direct (medical/drug) costs were measured as insurer payments to providers; indirect (absenteeism/presenteeism) costs were based on one-month recall of workplace performance (hours worked/missed, self-rated performance), estimated as (hours missed x self-reported hourly income). Annualized, inflation-adjusted (2006) costs were compared between compliant/non-compliant groups using multivariate models controlling for baseline characteristics. Analyses were conducted for all patients and a subsample of diagnosed depression patients.
Results:Among all patients (n=1,224), medical costs were numerically lower for compliant vs. non-compliant patients ($4,857 vs. $5,926, p=0.221); drug costs were significantly higher for compliant patients ($2,329 vs. $1,570, p=0.001). Indirect costs were not statistically different between compliant/non-compliant patients ($22,278 vs. $20,714, p=0.237). Among the depression subgroup (N=488), medical costs were numerically lower for compliant vs. non-compliant patients ($5,005 vs. $7,630, p=0.152) while drug costs were numerically higher for compliant patients ($2,550 vs. $1,829, p=0.153). Absenteeism costs were 30% lower for compliant patients ($7,725 vs. $11,040, p=0.038); presenteeism costs were not significantly different ($19,079 vs. $17,457, p=0.441).