Factors influencing the prescription of drugs of different price levels.

PURPOSE: Socioeconomic factors have been suggested to influence the prescribing of newer and more expensive drugs. In the present study, individual and health care provider factors were studied in relation to the prevalence of differently priced drugs. METHODS: Register data for dispensed drugs were retrieved for 18 486 individuals in a county council in Sweden. The prevalence of dispensed drugs was combined with data for the individual's gender, age, education, income, foreign background, and type of caregiver. For each of the diagnostic groups (chronic obstructive pulmonary disease [COPD], depression, diabetes, and osteoporosis), selected drugs were dichotomized into cost categories, lower and higher price levels. Univariate and multivariate logistic regressions were performed using cost category as the dependent variable and the individual and provider factors as independent variables. RESULTS: In all four diagnostic groups, differences were observed in the prescription of drugs of lower and higher price levels with regard to the different factors studied. Age and gender affected the prescription of drugs of lower and higher price levels more generally, except for gender in the osteoporosis group. Income, education, foreign background, and type of caregiver affected prescribing patterns but in different ways for the different diagnostic groups. CONCLUSIONS: Certain individual and provider factors appear to influence the prescribing of drugs of different price levels. Because the average price for the cheaper drugs versus more costly drugs in each diagnostic group was between 19% and 69%, there is a risk that factors other than medical needs are influencing the choice of drug.

Absorption of zinc and retention of calcium: dose-dependent inhibition by phytate.

The dose-dependent inhibitory effect of sodium phytate (myo-inositol-hexaphosphate) on absorption of zinc and retention of calcium was studied in man. No systematic study of this dose-response effect has been reported to this time. Forty subjects were served meals containing white wheat rolls without/with additions of phytate. Ten subjects were given test meals containing one or two of the studied levels of phytate and in addition all subjects were served meals to which no phytate was added. The zinc content was 3.1 mg (47 micromol) and the calcium content 266 mg (6.6 mmol). The rolls were labelled extrinsically with radioisotopes, 65Zn and 47Ca, and whole-body retention of both minerals was measured. Totally 105 meals were served, 36 meals in which no phytate was added and 9-10 meals on each level of phytate. The zinc absorption in meals to which either 0, 25, 50, 75, 100, 140, 175 or 250 mg of phytate-P (0, 134, 269, 403, 538, 753, 941 or 1344 micromol phytate) had been added was 22%, 16%, 14%, 11%, 7%, 7%, 7% and 6%, respectively (mean values). The addition of 50 mg phytate-P or more significantly decreased zinc absorption (p=0.01) as compared to absorption from the test meals with no added phytate. The calcium retention at day 7 in the same meals was 31%, 28%, 27%, 26%, 22%, 19%, 14% and 11% (mean values). The addition of 100 mg phytate-P or more significantly decreased calcium retention (p=0.03) compared to the test meals with no added phytate. It was concluded that the inhibitory effect of phytate on the absorption of zinc and the retention of calcium was dose dependent.