An explanation for the increase in heart disease mortality rates in diabetic Pima Indians: effect of renal replacement therapy.
OBJECTIVE
Diabetic nephropathy (DN) became the leading cause of death in diabetic Pima Indians in the 1970s, but was superseded by ischemic heart disease (IHD) in the 1980s. This study tests the hypothesis that the rise in the IHD death rate between 1965 and 1998 is attributable to access to renal replacement therapy (RRT).


METHODS
Underlying causes of death were determined among 2,095 diabetic Pima Indians > or = 35 years old during four 8.5-year time intervals. To assess the effect of access to RRT on IHD death rates, trends were reexamined after subjects receiving RRT were classified as if they had died of DN.


RESULTS
During a median follow-up of 11.1 years (range 0.01-34), 818 subjects died. The age- and sex-adjusted DN death rate decreased over the 34-year study (P = 0.05), whereas the IHD death rate increased from 3.3 deaths/1,000 person-years (95% CI 1.4-5.2) to 6.3 deaths/1,000 person-years (95% CI 4.5-8.0; P = 0.03). After 151 subjects on RRT were reclassified as if they had died of DN, the death rate for DN increased from 4.8 deaths/1,000 person-years (95% CI 2.6-7) to 11.3 deaths/1,000 person-years (95% CI 9-13.6; P = 0.0007), whereas the increase in the IHD death rate disappeared (P = 0.57).


CONCLUSIONS
The incidence rate of renal failure attributable to diabetes has increased rapidly over the past 34 years in Pima Indians. IHD has emerged as the leading cause of death due largely to the availability of RRT and to changes in the pattern of death among those with DN.
Pavkov
Meda E
ME
Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85011-4972, USA. mpavkov@phx.niddk.nih.gov
Sievers
Maurice L
ML
Knowler
William C
WC
Bennett
Peter H
PH
Nelson
Robert G
RG
D017677:Age Distribution; D001130:Arizona; D002423:Cause of Death; D003924:Diabetes Mellitus, Type 2 / Q000401:mortality*; D003925:Diabetic Angiopathies / Q000401:mortality; D003928:Diabetic Nephropathies / Q000628:therapy*; D005006:Ethnicity; D005260:Female; D006331:Heart Diseases / Q000401:mortality*; D006801:Humans; D015994:Incidence; D007198:Indians, North American; D007239:Infections / Q000401:mortality; D008108:Liver Diseases, Alcoholic / Q000401:mortality; D008297:Male; D009369:Neoplasms / Q000401:mortality; D017582:Renal Replacement Therapy; D012307:Risk Factors; D012727:Sex Characteristics; D012907:Smoking