Patient or Claim Characteristic^{†}

Adherence, expressed as absolute percent change in proportion of days covered

P value


$\sqrt[4]{\mathrm{Copayment}\phantom{\rule{.5em}{0ex}}\mathrm{in}\phantom{\rule{.5em}{0ex}}\mathrm{dollars}}$

8%

<0.0001

Medication class – inhaled steroid

49%

<0.0001

Zip codebased estimates of patients’ annual income^{‡}
 
$45 k – $75 k

6%

<0.0001

> $75 k

8%

<0.0001

Medication dosing frequency greater than once daily

4%

<0.0001


^{*}Variables without association, and therefore not used as predictors in this model, are: patient age, gender, history of depression (as evidenced by prior use of antidepressants), and patient race (as estimated from zip code data).

^{†}The referent categories were as follows: angiotensin receptor blocker medication class, annual income < $45 k annually, and medication dosing less than or equal to once daily.

^{‡}Estimated based on zip code data. 336 claims were excluded from this analysis due to missing zip code data.