Table 7

The impact of prescription drug charges on the use of generic or reference-priced drugs

Variable
Use of generics
Use of other substitutes
Studies

Co-payment
N/A
+
Esposito1 [45] (US, OS, CD, R)
Multi-tier formulary (vs. 1- or 2-tiers)
0
+
Huskamp et al. [125] (US, NS, CD, R); Motheral and Fairman [28] (US, NS, CD, R)
Multi-tier formulary (vs. 1- or 2-tiers)
0
N/A
Gibson et al. [90] (US, NS, PD, R); Motheral and Henderson [63] (US, NS, CD, R)
Multi-tier formulary (vs. 1- or 2-tiers)
N/A
+
Kamal-Bahl and Briesacher [91] (US, OS, CD, R); Landsman et al. [65] (US, NS, TD, R);
Co-insurance
0
N/A
Liebowitz et al. [48] (US, ES, CD, R); Newhouse [49] (US, ES, CD, R)
Mixed system
+
N/A
Hong and Shepherd [46] (US, OS, CD, NR); Mortimer [47] (US, OS, CD, R)
Reference pricing (non-RP drugs)
+
N/A
Marshall et al. [42] (CA, NS, TD, R); McManus et al. [43] (AU, NS, TD, R); Narine et al. [44] (CA, NS, TD, NR)
Reference pricing (non-RP drugs)
N/A
+
Mabasa and Ma [39] (CA, NS, CS, NR)

Country: AU = Australia; CA = Canada; US = United States

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

Type of data analyzed: CD = cross-sectional data; TD = time-series data; PD = panel data

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