Victor M. Hawthorne

Disparities in Incidence of Diabetic End-Stage Renal Disease According to Race and Type of Diabetes

The incidence of end-stage renal disease in patients with diabetes mellitus is reportedly higher among blacks than among whites. This finding may be explained by the greater prevalence of diabetes among blacks. The relation of the type of diabetes to the risk of diabetic end-stage renal disease is largely unstudied. We addressed these issues in a study of all the black and white diabetic patients with end-stage renal disease (470 blacks and 861 whites) reported to the Michigan Kidney Registry who began treatment during 1974 through 1983. We also reviewed the medical records of a subpopulation of such patients (284 blacks and 310 whites) who were less than 65 years of age at the start of treatment for end-stage renal disease to determine what type of diabetes they had. In this study, we made use of national data on the prevalence of diabetes. We found that the incidence of diabetic end-stage renal disease was 2.6-fold higher (P less than or equal to 0.0001) among blacks after we adjusted for the higher prevalence of diabetes among blacks, with the excess risk occurring predominantly among blacks with non-insulin-dependent diabetes mellitus (NIDDM). Most black patients with diabetic end-stage renal disease had NIDDM (77 percent), whereas most white patients with diabetic end-stage renal disease had insulin-dependent diabetes mellitus (IDDM) (58 percent) (P less than or equal to 0.0005 for the difference between the races). For both races combined, the risk of diabetic end-stage renal disease during the 10-year period we studied was markedly greater for patients with IDDM (5.8 percent) than for those with NIDDM (0.5 percent). Our results indicate an increased risk of diabetic end-stage renal disease among blacks as compared with whites, particularly blacks with NIDDM. Although the risk of diabetic end-stage renal disease is higher in patients with IDDM, the majority of patients with diabetic end-stage renal disease in the population we studied had NIDDM.

Relation between coronary risk and coronary mortality in women of the Renfrew and Paisley survey: comparison with men

Most epidemiological and intervention studies in patients with coronary artery disease have focused on men, the assumption being that such data can be extrapolated to women. However, there is little evidence to support this belief. We have completed a fifteen-year follow-up of 15,399 adults, including 8262 women, who lived in Renfrew and Paisley and were aged 45-64 years when screened between 1972 and 1976. We identified 490 deaths from coronary heart disease (CHD) in women and 878 in men. Women were more likely to have high cholesterol, to be obese, and to come from lower social classes than men, but they smoked less and had similar blood pressures. The relative risk--top to bottom quintile (95% Cl)--of cholesterol for coronary death after adjustment for all other risk markers was slightly greater in women (1.77 [1.45,2.16]) than in men (1.56 [1.32, 1.85]), but absolute and attributable risk were lower. Thus, women in the top quintile for cholesterol had lower coronary mortality (6.1 deaths per thousand patient years) than men in the bottom quintile (6.8 deaths per thousand patient years). Moreover, it was estimated that there would have been only 103 (21%) fewer CHD deaths in women, yet 211 (24%) fewer in men, if mortality had been the same for women and men in the lowest quintiles of cholesterol. Trends showing similar relative risks in these women, but lower absolute and attributable risks than in men, were present for smoking, diastolic blood pressure, and social class. There was no relation between obesity and coronary death after adjustment for other risks. Our results suggest that some other factors protect women against CHD. The potential for women to reduce their risk of CHD by changes in lifestyle may be less than for men.

Mortality in patients of the Glasgow blood pressure clinic

The mortality of 3783 non-malignant hypertensive patients attending the Glasgow Blood Pressure Clinic between 1968 and 1983 and followed for an average of 6.5 years was compared with that in three control groups: the general population of Strathclyde a group of 15 422 subjects aged 45-64 years and screened in Renfrew and Paisley between 1972 and 1976, and a group of hypertensives seen in a blood pressure clinic based on general practice in Renfrew. Average blood pressure for men at entry to the Glasgow Clinic was 181/111 mmHg falling to 158/96 mmHg during treatment. Corresponding values for women were 185/109 mmHg and 161/96 mmHg. Seven hundred and fifty clinic patients (451 males) died during follow-up, the commonest causes of death in both sexes being myocardial infarction and stroke. All-cause age-adjusted mortality (deaths per 1000 patient-years) was 41.4 for men and 22.1 for women. At all ages in both sexes and for all levels of initial blood pressure mortality was less in patients whose blood pressure was reduced most. Without a randomized control group it is not certain that lower mortality in those with well controlled blood pressure was due to treatment, although this is the most likely explanation. Cigarette smoking, a history of myocardial infarction, angina or stroke, retinal arterio-venous nipping, raised blood urea, an abnormal electrocardiogram (ECG) and secondary hypertension were associated with increased risk, but heavy alcohol intake, obesity, haematocrit greater than 45%, hypokalaemia and social class were not. Life table analysis showed that, despite some reduction of mortality by treatment, the relative risk to men and women in the clinic remained two- to five-times that of the general population. The benefits of treatment were not such as to restore normal expectation of life even when blood pressure was well controlled. Excess mortality in the clinic could not be explained by difference of smoking habit or social class. This suggests that there is in the hypertensive patients of the Glasgow Clinic an element of irreducible risk, that treatment may be beneficial in some respects but harmful in others, or that patients at particularly high risk are selectively referred to the clinic.

Neoplasms in Dialysis Patients: A Population-Based Study

Cancer incidence was assessed in 4,161 end-stage renal disease (ESRD) patients on dialysis to determine whether there was any excess risk of cancer in this population. Records from the Michigan Kidney Registry (MKR) for 1973 to 1984 were linked to those of the Michigan Cancer Foundations Metropolitan Detroit Cancer Surveillance System (MDCSS) to identify cases in the dialysis cohort. The expected number of cancers in the ESRD population was calculated using the race-, sex-, age- and calendar year-specific incidence rates of the tricounty metropolitan Detroit region of 4 million residents. The standardized incidence ratio (observed:expected) was significantly increased for all in situ tumors combined, as well as for invasive tumors of the kidney, the corpus uteri, and the prostate. The four-fold to five-fold excess (P less than 0.005) observed for renal and endometrial cancers, in addition to the significantly elevated (P less than 0.05) risk of prostate cancer indicates that patients maintained on dialysis should be evaluated for these tumors when they experience even minor symptoms. Population-based cancer and renal disease registries provide excellent opportunities for investigating etiologic hypotheses and future studies should incorporate potential risk factors when analyzing these data.

Birth weight of offspring and mortality in the Renfrew and Paisley study: prospective observational study.

Abstract Objective: To investigate the association between birth weight of offspring and mortality among fathers and mothers in the west of Scotland. Design: Prospective observational study. Participants: 794 married couples in Renfrew district of the west of Scotland. Main outcome measures: Mortality from all causes and from cardiovascular disease over 15 year follow up. Results: Women who had heavier babies were taller, had higher body mass index and better lung function, and were less likely to be smokers than mothers of lighter babies. Fathers of heavier babies were taller and less likely to be smokers than fathers of lighter babies. Mortality was inversely related to offsprings birth weight for both mothers (relative rate for a 1 kg lower birth weight 1.82 (95% confidence interval 1.23 to 2.70)) and fathers (relative rate 1.35 (1.03 to 1.79)). For mortality from cardiovascular disease, inverse associations were seen for mothers (2.00 (1.18 to 3.33)) and fathers (1.52 (1.03 to 2.17)). Adjustment for blood pressure, plasma cholesterol, body mass index, height, social class, area based deprivation category, smoking, lung function, angina, bronchitis, and electrocardiographic evidence of ischaemia had little effect on these risk estimates, although levels of statistical significance were reduced. Conclusions: Birth weight of offspring was related inversely to mortality, from all causes and cardiovascular disease, in this cohort. The strength of this association was greater than would have been expected by the degree of concordance of birth weights across generations, but an extensive range of potential confounding factors could not account for the association. Mortality is therefore influenced by a factor related to birth weight that is transmissible across generations. Key messages Low birth weight is associated with increased mortality from cardiovascular disease in later life, and birth weight is associated across generations so that both maternal and paternal birth weights are associated with the offsprings birth weight In this observational study we found that lower birth weight of offspring was associated with higher parental mortality from all causes and from cardiovascular disease This elevated mortality could not be explained by a range of social, environmental, behavioural, and physiological risk factors The strength of the association was greater than would have been expected by the degree of concordance of birth weights across generations We conclude that mortality is influenced by a factor that is related to birth weight and is transmissible across generations

Cardiorespiratory Disease in Men and Women in Urban Scotland: Baseline Characteristics of the Renfrew/Paisley(Midspan) Study Population

Study objective: To describe the distribution of risk factors, risk behaviours, symptoms and the prevalence of cardiorespiratory disease in men and women in an urban area with high levels of socioeconomic deprivation. A cross-sectional survey of 15,411 men and women aged 45–64, comprising an 80% response rate from the general population in Paisley and Renfrew, Scotland Main results: The main characteristics of the male Renfrew/Paisley population, compared to previous British studies, were shorter stature, higher blood pressure, a higher proportion of smokers who continue to smoke, lower FEV1 and higher levels of reported angina, breathlessness on effort and chronic bronchitis. In comparison with men, the main characteristics of the female Renfrew/Paisley population were shorter stature, higher plasma cholesterol, lower FEV1′ fewer current and ex-smokers, and a higher prevalence of breathlessness on effort. There were only small differences between men and women in the prevalence of angina, ECG evidence of myocardial ischaemia and chronic bronchitis. Conclusions: Middle-aged men and women in an urban area with high levels of socio-economic deprivation have different cardio- respiratory risk and disease profiles compared to previous population studies in the UK, based on occupational groups and random national samples.

Discontinuation of Dialysis Therapy as a Cause of Death

Discontinuation of life-sustaining dialysis therapy led to death in 282 of 5,208 patients who started therapy for end-stage renal disease (ESRD) in Michigan during 1980-1985 with a follow-up through 1986. Based on life table estimates at 60 months after initiation of therapy, 9.4% of patients overall died due to termination of dialysis, 11% of females versus 8% of males (p = 0.02), 0.1-3.4% for ages less than or equal to 49 years versus 56% for greater than 80 years, 12% for white versus 4% for black patients (p less than 0.001) and 16% for diabetic ESRD patients (higher than any other group, p less than 0.05). The Cox regression model confirms these significant findings for race, diabetes and age, and reveals a significant 60% increase in overall withdrawals for the years 1980-1985 (1.10/year, p less than 0.02). A separate analysis of discontinuation of dialysis as the percentage of all 2,564 dialysis deaths in prevalence cases for 1980-1984 revealed an overall ratio of 8.9% with a significant difference for ages less than or equal to 64 versus greater than or equal to 65 (p less than 0.001), race (p less than 0.001) but not for prior transplant failure or continuous ambulatory peritoneal dialysis therapy. Whereas the results for age and diabetes were expected, the significant increase of dialysis withdrawal over time and the racial difference are unexplained by information available at the Michigan Kidney Registry and indicate the need for exploration by further studies.

Independence in Activities of Daily Living for End-Stage Renal Disease Patients: Biomedical and Demographic Correlates

Factors associated with physical well-being were examined in a population-based sample of adult end-stage renal disease (ESRD) patients in Michigan (n = 459). The dependent variables were two measures of physical functioning: (1) a ten-item measure of activities of daily living (ADL), and (2) the 45-item physical dysfunction dimension of the Sickness Impact Profile (SIP). Independent variables included four modalities of treatment (in-center hemodialysis, continuous ambulatory peritoneal dialysis [CAPD], related transplant, and cadaver transplant); primary cause of ESRD (eg, diabetes, glomerulonephritis); comorbidity (other illnesses besides primary cause of ESRD); and demographic characteristics (sex, race, age, marital status, education). ADL and SIP unadjusted mean scores differed significantly by category for each of the eight study factors (analysis of variance [ANOVA], P less than 0.0001), with the exception of sex for SIP means. The highest levels of dependency in ADL were reported by patients who were older, female, black, widowed, less educated, treated with in-center hemodialysis, had diabetes as the primary cause of ESRD, and/or reported more comorbidity. The partial effect of each factor on the dependent measures with adjustment for the seven other factors was assessed using analysis of covariance (ANCOVA). In the ADL analysis, sex, race, age, primary cause of kidney failure, and comorbidity were significant factors (probability values ranging from 0.05 for race to 0.0001 for sex, primary cause of ESRD, and comorbidity). The SIP physical dysfunction measure gave slightly different results. Race, age, primary cause of ESRD, comorbid status, and modality of treatment were significantly related to physical dysfunction (P less than 0.05 to P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

BLOOD-LEAD AND HYPERTENSION

Blood and tap-water lead levels were examined in 135 hypertensives and 135 age and sex matched normotensives. Among male hypertensives there was a significant excess of cases with high blood-lead levels and a similar but statistically non-significant trend was found amongst female hypertensives. A positive correlation was found between blood-lead and tap-water lead. It is concluded that in the West of Scotland high blood-pressure is associated with high blood-lead levels, which might explain the high prevalence of cardiovascular disease in the area.

Excess smoking in malignant-phase hypertension

The smoking habits of 82 patients with malignant-phase hypertension were compared with those of subjects in three control groups matched for age and sex. Sixty-seven (82%) of the patients with malignant-phase hypertension were smokers compared with 41 (50%) and 71 (43%) of the patients in two control groups with non-malignant hypertension, and 43 people (52%) in a general population survey. The excess of smokers in the malignant-phase group was significant for men and women, together and separately, for cigarette smoking alone, and for all forms of smoking. There were no significant differences between the control groups. The chance of a hypertensive patient who smoked having the malignant phase was five times that of a hypertensive patient who did not. Twelve patients in the malignant-phase group had never smoked. All were alive three and a half years on average after presentation (range 11 months to seven years). Twenty-four (36%) of the smokers with malignant-phase hypertension died during the same period. The mortality rate was significantly higher among patients with renal failure, as was the prevalence of smoking. Eighteen patients with malignant-phase hypertension had a serum creatinine concentration higher than 250 μmol/l (2·8 mg/100 ml); 17 were smokers and one an ex-smoker. Eleven of these 18 patients died. It is concluded that hypertensive patients who smoke are much more likely to develop the malignant phase than those who do not, and that once the condition has developed it follows a particularly lethal course in smokers.