Table 5

The impact of prescription drug charges on patients' out-of-pocket expenditure on prescription drugs

Variable
Out-of-pocket expenses
Studies

Co-payment
+
Stuart and Zacker [123] (US, OS, CD, R)
Co-payment
0
Lurk et al. [27] (US, NS, CD, R)
Multi-tier formulary (vs. 1- or 2-tiers)
+
Huskamp et al. [124] (US, NS, CD, R); Huskamp et al. [125] (US, NS, CD, R); Kamal-Bahl and Briesacher [91] (US, OS, CD, R)
Reference pricing
+
Grootendorst et al. [101] (CA, NS, TD, R)
Insurance coverage


     Supplementary (vs. none)
-
Alan et al. [69] (CA, OS, CD, R); Alan et al. [68] (CA, OS, CD, R); Alan et al. [126] (CA, OS, CD, R); Blustein [127] (US, OS, CD, R); Federman et al. [114] (US, OS, CD, R)
     Reimbursement limit
+
Tseng et al. [128] (US, OS, CD, NR)

Country: CA = Canada; US = United States

Type of study: ES = experimental study; NS = natural study; OS = observational study

Type of statistical analysis used: R = regression techniques; NR = no regression techniques

Gemmill et al. International Journal for Equity in Health 2008 7:12   doi:10.1186/1475-9276-7-12