A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation☆

Systematic review and meta-analysis

Estimates of the worldwide incidence, mortality and prevalence of 26 cancers in the year 2002 are now available in the GLOBOCAN series of the International Agency for Research on Cancer. The results are presented here in summary form, including the geographic variation between 20 large "areas" of the world. Overall, there were 10.9 million new cases, 6.7 million deaths, and 24.6 million persons alive with cancer (within three years of diagnosis). The most commonly diagnosed cancers are lung (1.35 million), breast (1.15 million), and colorectal (1 million); the most common causes of cancer death are lung cancer (1.18 million deaths), stomach cancer (700,000 deaths), and liver cancer (598,000 deaths). The most prevalent cancer in the world is breast cancer (4.4 million survivors up to 5 years following diagnosis). There are striking variations in the risk of different cancers by geographic area. Most of the international variation is due to exposure to known or suspected risk factors related to lifestyle or environment, and provides a clear challenge to prevention.

https://acsjournals.onlinelibrary.wiley.com/doi/pdf/10.3322/canjclin.55.2.74

Global cancer statistics, 2002.

Background Patients with congestive heart failure have a high mortality rate and are also hospitalized frequently. We studied the effect of an angiotensin-converting-enzyme inhibitor, enalapril, on mortality and hospitalization in patients with chronic heart failure and ejection fractions less than or equal to 0.35. Methods Patients receiving conventional treatment for heart failure were randomly assigned to receive either placebo (n = 1284) or enalapril (n = 1285) at doses of 2.5 to 20 mg per day in a double-bind trial. Approximately 90 percent of the patients were in New York Heart Association functional classes II and III. The follow-up averaged 41.4 months. Results There were 510 deaths in the placebo group (39.7 percent), as compared with 452 in the enalapril group (35.2 percent) (reduction in risk, 16 percent; 95 percent confidence interval, 5 to 26 percent; P = 0.0036). Although reductions in mortality were observed in several categories of cardiac deaths, the largest reduction occurred among the deaths attributed to progressive heart failure (251 in the placebo group vs. 209 in the enalapril group; reduction in risk, 22 percent; 95 percent confidence interval, 6 to 35 percent). There was little apparent effect of treatment on deaths classified as due to arrhythmia without pump failure. Fewer patients died or were hospitalized for worsening heart failure (736 in the placebo group and 613 in the enalapril group; risk reduction, 26 percent; 95 percent confidence interval, 18 to 34 percent; P less than 0.0001). Conclusions The addition of enalapril to conventional therapy significantly reduced mortality and hospitalizations for heart failure in patients with chronic congestive heart failure and reduced ejection fractions.

Effect of enalapril on survival in patients with reduced left ventricular ejection fractions and congestive heart failure.

Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials

A retrospective comparison of cancer incidence data and, where relevant, population data with 16 955first-time users (patients, relatives and friends) of a national cancer information service (CancerBACUP) during the period April1995 to March 1996 is presented. The number of events observed was compared with the number of events expected, were the nationalrates of cancer incidence and population demographics apply. Standardized incidence ratios (SIRs) (observed – expectedratios) were used to indicate any differences. Statistically significant differences (P< 0.001) in the observed andexpected sex, age and primary site distribution of patients enquired about were found. Statistically significant differences(P< 0.001) were also identified for the age, employment status, socioeconomic class and geographical location offirst-time enquirers (patients, relatives and friends). Enquiries about brain, testis and breast cancers and non-Hodgkin'slymphoma (NHL) were substantially higher than expected; enquiries about bladder, lung, stomach and colorectal cancers were muchlower than expected. As the service is provided via a freephone number, it is available to all, and users might be expected to berandomly distributed across the variables listed. The underlying reasons for the differences identified need to be investigated,and the role of information in the care of cancer patients should be formally evaluated. © 1999 Cancer Research Campaign

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An analysis of first-time enquirers to the CancerBACUP information service: variations with cancer site, demographic status and geographical location.

Loss to follow-up: does it matter?

Summary— As part of a prospective cohort study of 388 men undergoing transurethral resection of the prostate (TURP) for benign prostatic hypertrophy, pre-operative factors and the outcome of surgery during the first post-operative year were compared between patients in whom their surgeon felt the principal reason for operating was chronic retention (37%), acute retention (with no chronic retention) (28%), or symptomatic prostatism (with no history of chronic or acute retention) (35%).

Although in many respects the patients in the 3 diagnostic categories were similar, patients with chronic retention were more likely to be younger, of higher social class and to have worse general health. Patients with acute retention were more likely to present with a urinary tract infection and to have electrocardiographic abnormalities, and symptomatic patients presented with more severe urinary symptoms.

Minor differences between the categories with regard to post-operative morbidity and mortality were not statistically significant at the 5% level. However, some significant differences did exist. Patients with acute retention were more likely to experience urinary and non-urinary infections and impotence after surgery, while symptomatic patients reported less improvement in their health status as regards pain and social isolation.

These results suggest that the method of categorisation is clinically valid and a necessary distinction to make when auditing TURP.

Differences in outcome of transurethral resection of the prostate for benign prostatic hypertrophy between three diagnostic categories

https://jech.bmj.com/content/jech/52/10/612.full.pdf

Wider "causal thinking in the health sciences".

Data from an ongoing case-control study of breast cancer were used to analyze the reason women with breast cancer tend to have a later 1st term pregnancy than controls. The 655 cases with breast cancer had their 1st term birth at a mean age of 25.38 years compared with 24.18 years for controls. The mean interval between age at onset of sexual intercourse and 1st birth was 3.08 years among cases and 2.82 among controls. That is about 80% of the differences between women with breast cancer and matched controls with regard to age at 1st term birth was accounted for by differences between the groups in age at onset of sexualy activity. Women with breast cancer reported 1.32 years/woman of contraceptive use before 1st pregnancy compared with 1.09 years/woman among controls. However there was little difference between the 2 groups either in the reported duration of unprotected intercourse preceding the 1st planned conception or in the reported frequency with which intercourse took place during that period. Finally multivariate analysis indicated that the reason women with breast cancer tended to have a later 1st term pregnancy than controls is because they tended to start intercourse at a later age and to use contraception more. There was no evidence that women with breast cancer were less fertile than unaffected controls. These findings support the view that the higher risk of breast cancer in women having a later 1st birth is attributable to early pregnancy itself having a direct protective effect against the disease.

Klim McPherson

Papers

An analysis of first-time enquirers to the CancerBACUP information service: variations with cancer site, demographic status and geographical location.

Loss to follow-up: does it matter?

Differences in outcome of transurethral resection of the prostate for benign prostatic hypertrophy between three diagnostic categories

Wider "causal thinking in the health sciences".

Fertility in relation to the risk of breast cancer.