Table 12

The impact of prescription drug charges on adherence to treatment

Variable

Compliance

Study

Co-payment

-

Atella et al. [76] (IT, NS, CD, R); Gibson et al. [191] (US, OS, CD, R); Poirier et al. [77] (CA, NS, TD, NR)

Co-payment

0

Poirier et al. [77] (CA, NS, TD, NR)

Multi-tier formulary (vs. 1- or 2-tiers)

-

Landsman et al. [65] (US, NS, TD, R); Shrank et al. [79] (US, OS, CD, R); Taira et al. [80] (US, OS, CD, R)

Co-insurance

-

Reuveni et al. [192] (IS, OS, CD, R)

Mixed system

-

Ellis et al. [193] (US, OS, CD, R); Goldman et al. [194] (US, OS, CD, R); Mojtabai and Olfson [195] (US, OS, CD, R); Piette et al. [196] (US, OS, CD, R)

Change from

co-payment to deductible and co-insurance

0

Pilote et al. [30] (CA, NS, CD, R)

Has co-insurance (vs. has co-payment)

-

Dor and Encinosa [78] (US, OS, CD, R)

Insurance coverage

Primary (vs. none)

+

Kennedy and Erb [197] (US, OS, CD, NR); Piette et al. [196] (US, OS, CD, R); Thomas et al. [144] (US, OS, CD, R)

Primary public (vs. private)

-

Dodrill et al. [198] (US, OS, CD, NR)

Supplementary (vs. none)

+

Col et al. [199] (US, OS, CD, R); Safran et al. [200] (US, OS, CD, R); Schoen et al. [74] (US, NS, CD, NR); Steinman et al. [201] (US, OS, CD, R)

Prescription limit

-

Cox et al. [35] (US, OS, CD, R); Schulz et al. [81] (US, NS, CD, NR)

Country: CA = Canada; IS = Israel; IT = Italy; 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