The paper presents an approach to the analysis of data that contains (multiple) structural changes in a linear regression setup. We implement various strategies which have been suggested in the literature for testing against structural changes as well as a dynamic programming algorithm for the dating of the breakpoints in the R statistical software package. Using historical data on Nile river discharges, road casualties in Great Britain and oil prices in Germany it is shown that changes in the mean of a time series as well as in the coefficients of a linear regression are easily matched with identifiable historical, political or economic events.
Patients with type 2 diabetes on dialysis are at a substantially increased risk of cardiovascular and cerebrovascular diseases. Dyslipidemia characterized by moderately elevated low-density lipoprotein cholesterol and high triglycerides and low high-density lipoprotein cholesterol levels is common in this population. We hypothesized that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors would reduce vascular morbidity and mortality in this patient group. The ‘Deutsche Diabetes Dialyse Studie’ (4D study) is a prospective, randomized, double-blind study involving 178 dialysis centers throughout Germany. Between March 1998 and October 2002, 1,255 patients were randomized to either atorvastatin 20 mg or placebo; 677 men and 578 women, aged 30–83 years, have been enrolled. The study will be terminated as soon as the predefined number of 424 patients with primary combined end points (i.e., cardiovascular death, nonfatal myocardial infarction, or fatal/nonfatal stroke) will have occurred. The total cohort had the following characteristics at baseline: the mean age was 65.7 years, 54% were men, 89% had a history of hypertension, 21% had coronary artery disease, 17.8% had a history of stroke or a transient ischemic attack, and 45% suffered from peripheral arterial disease. The mean time interval between the diagnosis of diabetes and the onset of dialysis was 17.4 years. On average, the patients were on hemodialysis for 8.3 months. Mean lipid and lipoprotein levels were: total cholesterol 219 ± 43 mg/dl, low-density lipoprotein cholesterol 126 ± 30 mg/dl, high-density lipoprotein cholesterol 36 ± 13 mg/dl, and triglycerides 264 ± 167 mg/dl. The results of the study will provide important information on the efficacy and safety of atorvastatin to support its use in patients with an impaired renal function who are at a high risk of vascular morbidity and mortality.
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