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Background:The long-term effect of a low-protein diet on the progression of chronic kidney disease is unknown. We evaluated effects of protein restriction on kidney failure and all-cause mortality during extended follow-up of the Modification of Diet in Renal Disease Study. Methods:Study A was a randomized controlled trial from 1989 to 1993 of 585 patients with predominantly nondiabetic kidney disease and a moderate decrease in glomerular filtration rate (25 to 55 mL/min/1.73 m2[0.42 to 0.92 mL/s/1.73 m2]) assigned to a low- versus usual-protein diet (0.58 versus 1.3 g/kg/d). We used registries to ascertain the development of kidney failure (initiation of dialysis therapy or transplantation) or a composite of kidney failure and all-cause mortality through December 31, 2000. We used Cox regression models and intention-to-treat principles to compute hazard ratios for the low- versus usual-protein diet, adjusted for baseline glomerular filtration rate and other factors previously associated with the rate of decrease in glomerular filtration rate. We estimated hazard ratios for the entire follow-up period and then, in time-dependent analyses, separately for 2 consecutive 6-year periods of follow-up. Results:Kidney failure and the composite outcome occurred in 327 (56%) and 380 patients (65%), respectively. After adjustment for baseline factors, hazard ratios were 0.89 (95% confidence interval [CI], 0.71 to 1.12) and 0.88 (95% CI, 0.71 to 1.08), respectively. Adjusted hazard ratios for both outcomes were lower during the first 6 years (0.68; 95% CI, 0.51 to 0.93 and 0.66; 95% CI, 0.50 to 0.87, respectively) than afterward (1.27; 95% CI, 0.90 to 1.80 and 1.29; 95% CI, 0.94 to 1.78; interaction P= 0.008 and 0.002, respectively). Limitations include lack of data for dietary intake and clinical conditions after conclusion of the trial. Conclusion:The efficacy of a 2- to 3-year intervention of dietary protein restriction on progression of nondiabetic kidney disease remains inconclusive. Future studies should include a longer duration of intervention and follow-up.

C-Reactive protein (CRP) level is elevated in kidney failure and may be related to malnutrition and cardiovascular disease (CVD). Data are limited regarding relationships between CRP levels and glomerular filtration rate (GFR), nutritional indices, and CVD in patients with earlier stages of kidney disease.

Cotton textile workers have an increased prevalence of both obstructive and restrictive lung function patterns compared with control subjects. Similar abnormal patterns may occur with respiratory diseases of other etiologies, notably those associated with cigarette smoking. The shape of the maximum expiratory flow volume (MEFV) curve has been used to characterize patterns of lung function abnormality. To better evaluate the respiratory effects of cotton dust exposure and to contrast them with those of cigarette smoking, we defined a new functional parameter (angle β) related to the shape of the MEFV curve. We compared 477 cotton textile workers, both current smokers and never smokers, 45 years and older, with 932 similarly aged control subjects from three communities. Smokers, regardless of their occupational exposure or sex, have smaller β values than nonsmokers. Cotton textile workers, despite a greater prevalence of abnormal lung function, have β values that do not differ from those of persons without occupational exposure to cotton dust. We suggest that morphologic patterns of flow volume curves reflect separate effects of cotton dust exposure and smoking and may be related to different sites of airway injury.

The records of 340 infants of 36 weeks' gestational age or less were reviewed to study the relationship between premature rupture of the membranes (PRM) and the development of the respiratory distress syndrome (RDS). Twins and infants of diabetic mothers were excluded from the data analysis. PRM of 16 hours or more was associated with a statistically significant reduction in the incidence of RDS in infants of 31 weeks' gestational age and older. The association between PRM in excess of 16 hours and survival, however, was only statistically significant for infants of 33 weeks' gestational age and older. The implications of these results and a proposed plan of management for premature infants with PRM are discussed.

Differences in the shape of the maximum expiratory flow volume (MEFV) curve have been associated with pathologic states and physiologic differences between normal individuals. We describe variations in a new parameter, angle p, which characterizes the general configuration of the MEFV curve among healthy subjects and subjects with disease in 5,140 white individuals. Women had consistently larger β angles than men. There was a progressive decline in β with advancing age. Cigarette smokers had lower β angles than did lifetime never-smokers. Subjects with abnormal lung (unction patterns had lower β angles than individuals with a normal pattern. Finally, individuals with asthma, chronic bronchitis, dyspnea and wheezing had significantly lower β angles than healthy individuals. Further clinical and epidemiologic studies are needed to evaluate this measurement's possible value in pulmonary function evaluation. (Chest 1988; 94:799-806)

• In 100 consecutive patients undergoing mechanically assisted ventilation, we prospectively determined immediate survival, hospitalization charges, and subsequent one-year outcome. Sixty percent of the patients survived the episode of assisted ventilation. This survival decreased to 50% at the time of hospital discharge and to 33% one year after hospitalization. There were no posthospitalization deaths in patients less than age 50 years. In those patients older than 70 years, however, 51% were dead by the time of hospital discharge and 73% died by one year following discharge. Comparison of features that reflect the magnitude of intensive respiratory care, such as hours of ventilation and intensive care unit (ICU) length of stay, disclosed no statistically significant differences between survivors and nonsurvivors at discharge. Hospitalization charges averaged $10,968 per patient. The total charge for respiratory therapy services (including arterial blood gas determinations) averaged $2,200. Respiratory care service charges were only marginally different between survivors and nonsurvivors. By contrast, total charges and total length of stay were greater for the survivors. Resource use in the intensive care setting as reflected by hours of mechanical ventilation and ICU length of stay was similar in both survivors and nonsurvivors, with the larger total cost for survivors relating primarily to care outside the ICU. Also, we confirm that prognosis is excellent in patients less than 50 years of age who survive mechanically assisted ventilation for acute respiratory failure and that extubation in elderly patients is not necessarily indicative of a good prognosis.(Arch Intern Med 1985;145:235-239)

Intermittent mandatory ventilation (IMV) was introduced to facilitate the weaning of patients from mechanical ventilation. The outcome of ventilator management in 116 patients who were treated in the first three months of 1975 was compared retrospectively with that of 135 patients who were treated in the first three months of 1976. All patients who were treated in 1975 received conventional (assisted or controlled) mechanical ventilation. In 1976, seventy-seven patients (57%) were treated with the use of IMV, and 58 (43%) were treated with the use of conventional mechanical ventilation. Sixty-five patients who were treated in 1976 with the use of IMV were matched with patients who were treated in 1975 with the use of conventional ventilation, on the basis of age, sex, race, history of pulmonary disease, smoking history, diagnosis, service, and location of therapy. The average time spent on a ventilator by the IMV patients was 145 hours, whereas the matched control patients spent 142 hours. The length of hospitalization was 36 days for the IMV patients and 30 days for the control patients. These time periods were not significantly different and indicate that IMV did not reduce the length of ventilator management.(JAMA 1981;246:1210-1214)

This paper proposes a generalized logistic regression model that can account for the correlation among responses on subunits. The subunits may arise as data on multiple observations within an individual. This method generalizes earlier work by Rosner (1984 a,b) and others. Methodological generalizations include: (1) the use of the more general Polya-Eggenberger distribution instead of the beta-binomial distribution to model the correlation structure, so that cases with negative, positive, or zero intraclass correlation can be handled; (2) a stepwise approach; (3) linear and non-linear regression; and, (4) the inclusion of the case of a truncated distribution. The model can accommodate missing data and covariates on the unit and subunit level. The derivative-free simplex algorithm is used to estimate the parameters.The model is applied to data describing the progression of obstruction in coronary disease where multiple arterial segments are studied for each patient. The correlation in response that may exist for these multiple segments is accounted for in the analyses while attempting to examine associations with individual-specific (e.g., history of diabetes) and segment-specific (e.g., initial percent stenosis) covariates. Analyses were performed on a data set describing 382 patients with unoperated coronary artery disease and two coronary angiograms separated by at least one month and on a data set describing 284 patients undergoing percutaneous transluminal coronary angioplasty and studied by coronary angiograms.

Most seemingly healthy persons challenged with an aerosol of cotton bract extract develop some degree of bronchospasm. The role of nonspecific reactivity of the airways in this reaction to cotton bract extract is undefined. We examined the relationship between airway responses to cotton bract extract and to methacholine, as well as between airway responses to cotton bract extract and to a bronchodilator. Twenty-two healthy subjects were screened for sensitivity to inhaled cotton bract extract. Pulmonary function was measured using partial expiratory flow-volume curves on which flow at 60 percent of the control vital capacity below total lung capacity was measured (MEF40%[P]) following ten minutes of inhalation of cotton bract extract. In the group screened, 12 were found to be responders to the extract, with drops in MEF40%(P) of 20 percent or more, and ten were found to be nonresponders. On separate days, we measured the responses of our subjects* airways to inhaled metaproterenol and methacholine. The mean threshold dose for methacholine in the responding group was 26.8 mg/ml, as compared to 55.6 mg/ml for the nonresponders (f = 2.52; p < 0.05). Furthermore, the mean percent increase in MEF40%(P) following inhalation of metaproterenol was 41 percent in responders and 24 percent in nonresponders (t= 2.19; p < 0.05). We conclude that some responders to cotton bract extract exhibit greater reactivity of the airways than nonresponders.

Glomerular filtration rate (GFR) estimation based on creatinine and cystatin C (eGFRcr-cys) is more accurate than estimated GFR (eGFR) based on creatinine or cystatin C alone (eGFRcror eGFRcys, respectively), but the inclusion of creatinine in eGFRcr-cysrequires specification of a person’s race. β2-Microglobulin (B2M) and β-trace protein (BTP) are alternative filtration markers that appear to be less influenced by race than creatinine is.