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R S Porter

Publications and source records attributed to R S Porter.

45 records · Page 3Linked to original sources
PubMed1982

A multicenter evaluation of variables affecting the predictability of creatinine clearance.

Data from 722 urine collections (627 patients) from 14 medical facilities were used to compare measured creatinine clearance values with clearance estimates calculated using three "urine-free' mathematical formulas. The influence of two patient weight variables (actual weight, lean body weight) and the level of renal function on clearance prediction was assessed. In addition, site parameters (region, facility), time parameters (month, day, day of the week), and patient parameters (age, sex, height, weight, diagnoses) were evaluated for their statistical influence on the relationship between measured clearance and estimates calculated with one of the methods. Strong, statistically significant correlations were observed between clearance values estimated with each prediction method and measured clearances. Although statistical differences were noticed between mean values predicted with each method, these differences were clinically insignificant. Use of lean body weight for calculation of creatinine excretion produced clearance estimates that were significantly lower than those obtained with actual weight and substantially closer to measured clearance values. Among patient variables, age and two specific diagnoses (congestive heart failure and pregnancy), were statistically associated with variability in the relationship between measured and predicted clearance. Interregional and interfacility differences in the measured-predicted clearance relationship, variability associated with the day of the week of collection, and tendency of the urine-free formulas to over-predict clearance support potential inaccuracy of measured clearance determination. The results suggest that inaccuracies in clearance determination, rather than inadequacies of urine-free prediction methods, account for the majority of the observed variability in the relationship.

Age Factors↗
PubMedDate not supplied

Impact of cost problems on morbidity in a hypertensive population.

Researchers disagree about the extent to which limited access to health services negatively affects health. In this study, we investigated the association of health status with access to high blood pressure medication among hypertensive respondents drawn from two random household surveys conducted in the state of Georgia during 1981 and 1983. We compared hypertensive respondents reporting difficulties in paying for medication (n = 616) with hypertensive respondents not reporting cost problems (n = 616) who were matched on race, sex, age (+/- 3 years), and per capita family income (+/- $3,000). Because questions were not identical in the 1981 and 1983 surveys, we compared responses of the matched groups separately for each year in the analysis. In the 1981 comparison, a significantly higher (P less than .05) percentage of hypertensive individuals experiencing cost problems reported being in fair or poor health (60.5%) and having had a stroke (11.4%) than those without cost problems (39% for fair or poor health status and 5% for occurrence of stroke). Those with cost problems also reported a higher frequency of cardiac problems (24.6%) than those without cost problems (18.1%), although these differences are not statistically significant (P greater than .05). In the 1983 survey, a significantly larger number of those with cost problems (57.4%) reported being in fair or poor health than those without cost problems (43.1%, P less than .05).

Antihypertensive Agents↗