The Effect of Increased Prescription Drug Cost-Sharing on Medical Care Utilization and Expenses of Elderly Health Maintenance Organization Members

Abstract

No consistent relationships were observed between increased copayments per dispensing and medical care utilization and expense. Future research needs to address the impact on the classes of medications received and related health status, and the impact of larger increases in copayments per dispensing on medical care and health-related factors.

Effect of Prescription Drug Coverage on the Elderly's Use of Prescription Drugs

“…Johnson et al (1997) and Hsu et al (2006) used elderly individuals enrolled in Kaiser-Permanente managed care plans. Johnson et al (1997) reported that a $2 (66%) increase in the copayment among members of the Kaiser-Permanente Northwest Division (e.g., Portland and Seattle) in the period 1988 to 1990 resulted in an 8% decrease in prescription use. Hsu et al (2006) looked at the impact of benefit caps on prescription drug use among elderly people enrolled in the Kaiser-Permanente Northern California Division, and found that caps lowered expenditures on prescription drugs by 31%.…”

“…In sum, few would argue with the conclusion that prescription drug insurance increases use of prescription drugs; however, the magnitude of the effect remains in doubt regardless of whether the group of interest is the general population, participants in a specific type of insurance plan, or the chronically ill. One potential explanation of the different estimates relates to methods and the fact that relatively few studies have addressed the possible nonrandom selection of elderly people into insurance. Arguably, the more persuasive studies are those based on natural experiments (Chandra, Gruber, and McKnight 2007;Hsu 2006;Johnson 1997;Soumerai et al 1991;Lichtenberg and Sun 2007;Yin et al 2008). Yang, Gilleskie, and Norton (2004) and Shea et al (2007) also addressed selection through the use of instrumental variables, but both studies found little evidence of selection bias after conditioning on health and past use of medical care.…”

Effect on Drug Utilization and Expenditures of a Cost-Share Change From Copayment to Coinsurance

“…3 Patientc ost-sharing throughacopaymento rc oinsurance is onecommontechnique forinfluencing patientutilization of medications.Previousresearchinthisareahas shownthatincreasing patientc ost-share decreasesm edicationu se. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, only a fewo ft hese studiesu tilizeds trongr esearchd esigns,s ucha sa pre-post intervention design with ac omparatorg roup. [6][7][8]14,16,17,19 Also,few studiesexamine thechanges seen in larger cost-sharing differencesinanadult,commercialinsurance population.…”

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, only a fewo ft hese studiesu tilizeds trongr esearchd esigns,s ucha sa pre-post intervention design with ac omparatorg roup. [6][7][8]14,16,17,19 Also,few studiesexamine thechanges seen in larger cost-sharing differencesinanadult,commercialinsurance population. 8,14 Thechallenge when increasing patientcost-share is to ensure that patients do notf orgo valuable treatments as ar esulto f theg reater cost-share.R esearchh as shownt hat2 -tier benefit designs, usedt oi nfluence thec hoice of treatmenti nf avor of lower-cost genericmedications,decreased drug expenditures and utilization over single-tierprogramsbut still didnot differentiate betweenmoreand less valuable brandnametreatments.…”

“…Some studiesh ave compared thee ffectso fi ncreased copayments and increasedcoinsurance ratesondrugutilization andmedical care utilization in elderly populationsi nt he United States andh ave foundad ecreaseinexpendituresand utilization with no subsequentchangeinmedical expenses. 16,17 More recentresearchintocoinsurance hasexaminedthe effect of coinsuranceo ns elf-monitoring of blood glucoseb yd iabetic patients andonadherence ratestobeta-blockertherapy. 31,32 In the studyo fd iabeticp atients, dailyu tilization of glucosem onitoringt ests tripsd eclined afterthe plan switchedfromn om ember cost-sharing to coinsurance, butt he amount of change wasn ot clinically significant.…”