Distribution of hypertension and renal disease in Oregon

Expecting to find agreement between the geographic distribution of hypertension and renal disease, we developed regional mortality rates for 1950-72 and prevalence rates for a Selective Service cohort born in 1939-41 and examined during 1957-69. For this purpose the State's counties were grouped into eight geographically homogeneous regions. The general decline in hypertension mortality was most pronounced in Portland, Oregon's major urban center. However, the decline halted during 1968-72 in the southern Cascade region which has become an area of relatively higher risk within the State. During these 23 years nephritis mortality fell, kidney infection mortality was stable, and both syndromes showed peak mortality in other, different regions of the State. The geographic pattern of hypertension prevalence among the draftee cohort resembled the 1963-67 hypertension mortality pattern, but more recent morbidity data are needed to confirm the southern Cascade region's recent change to a high-risk area. Of 529 draftees with diagnosed hypertension, only 35 percent of the cases were previously known, only 7 percent has had any previous treatment, and only 7 percent were associated with known renal conditions. Among 521 registrants with a history of renal disorders, the prevalence of hypertension was increased for all categories of renal disease but was significantly high only for those with a history of glomerulonephritis. To date in Oregon we have found no evidence that renal disorders are major determinants of hypertension morbidity or mortality.

Endogenous creatinine clearance as a clinical measure of glomerular filtration rate

Endogenous creatinine clearance was assessed by inulin in 91 simultaneous studies in 41 patients and proved an accurate measurement of glomerular filtration rate. For filtration rates <20 ml/min the creatinine clearance may slightly overestimate the glomerular filtration rate. Successive determinations of filtration rate by either method may vary by 20% even though the methods agree with each other. Glomerular filtration rate itself is variable, and in its clinical usage this should be recognized.