The impact of selected patient characteristics on practitioners' treatment recommendations for end-stage renal disease.

Medical decision making under uncertainty was tested using an empirical study of practitioner judgments concerning the preferred treatment(s) for end-stage renal disease (ESRD) patients. Patient-specific factors were varied systematically in written case vignettes, which were mailed to physician and nonphysician practitioners who treated ESRD patients in Canada and Michigan. Respondents were asked to indicate for each vignette: a preferred treatment and all other acceptable treatments. Overall patterns of choice were analyzed; the clear preferences shown for certain treatment modalities (e.g., for continuous ambulatory peritoneal dialysis over home hemodialysis) have planning implications. The apparent receptivity to new ESRD treatments may affect the success of government policies aimed at encouraging greater use of home hemodialysis. The impact of each patient-specific variable on treatment choice was also examined. Factors such as the patient's age proved to be major determinants both of the preferred treatment modalities and of the number of alternatives considered acceptable. The research method allowed areas of medical consensus to be distinguished from those 'grey areas' in which patient characteristics alone could not explain treatment selection. The resulting 'controversy' cases are being used as the dependent variables in further studies.

Determinants of size at birth in a Canadian population.

Anthropometric, medical, and sociodemographic characteristics and smoking habit of a random sample of postpartum women in a Canadian population were determined. These characteristics were analyzed in relation to the birth size of their babies. With controls for gestational age and fetal sex, the following maternal variables were positively correlated with birth weight: prepregnant weight, weight gain in pregnancy, stature, bicristal and biacromial diameter, calf and upper arm circumference, and triceps and subscapular skinfold thickness. Smoking during pregnancy reduced birth weight by 13 gm per cigarette smoked daily. Similar associations of maternal size and smoking habit were observed with respect to infant length, head circumference, and chest circumference. The predictors of birth weight are proposed for use in adjusting upward or downward the population distribution of birth weight to reflect the individual characteristics of the mother.

Size-at-birth standards for an urban Canadian population.

By random sampling of all births occurring in Hamilton, Ont. over an 18-month period the percentile distributions of the newborn infants' weight, length, and head and chest circumferences were determined. The resulting standards may be used in the clinical evaluation of size for gestational age. The smoothed 50th percentile values for newborns of 40 weeks gestational age were as follows for boys and girls respectively: birth weight 3530 and 3355 g, crown-heel length 52.0 and 51.3 cm, head circumference 35.2 and 34.4 cm, and chest circumference 33.4 and 32.8 cm. The mother's height averaged 160.8 +/- 6.1 cm and her weight before the pregnancy 59.2 +/- 10.5 kg. The prevalence of cigarette smoking during pregnancy was 34.8%.