2010年10月26日 星期二

為何偏好洗血管不洗腹膜?

Hemodialysis vs. Peritoneal Dialysis
Outcomes are comparable, but few patients chose peritoneal dialysis.

Patients with end-stage renal disease (ESRD) have better outcomes with kidney transplant than with dialysis. However, about 100,000 ESRD patients start dialysis annually because of limited donor organs or contraindications to transplantation; about 7% start with peritoneal dialysis (PD). In two U.S. studies, researchers address outcomes of and preferences for PD and hemodialysis (HD).

In one study, 685,000 HD and PD patients were assessed in 3-year cohorts from 1996 to 2004; mortality at 5 years of follow-up was evaluated. Compared with HD patients, PD patients were younger, healthier, and more likely to be white. In analyses adjusted for these factors, PD patients had somewhat higher risk for death (about 8% higher) than HD patients between 1996 and 2001, but no difference was noted from 2002 to 2004. The analyses also were adjusted for the greater likelihood that PD patients are selected for transplant. Median survival after dialysis initiation was 36.6 months for PD patients and 38.4 months for HD patients.

In another study, about 1600 ESRD patients were surveyed from 2005 to 2007; nearly 1000 (61%) were counseled about PD, of whom 108 (11%) started PD. Of the 631 patients who did not receive PD counseling, only 10 (1.6%) started PD. Patients who chose PD were younger, healthier, and more likely to be employed. In analyses controlled for demographic and clinical factors, rates of PD use varied substantially across major dialysis centers.

Comment:
Outcomes with PD are similar to those with HD, and PD costs about US$20,000 less annually, yet — strikingly — a substantial proportion of patients do not receive counseling about PD. An editorialist notes that nephrologists report decreasing experience with PD and, therefore, are increasingly uncomfortable counseling patients about it, which leads to a downward spiral of counseling and use. A new Medicare benefit that provides for six sessions of counseling about dialysis options could help reverse this trend.


Thomas L. Schwenk, MD
Published in Journal Watch General Medicine October 26, 2010

Citation(s):
Mehrotra R et al. Similar outcomes with hemodialysis and peritoneal dialysis in patients with end-stage renal disease. Arch Intern Med 2010 Sep 27; [e-pub ahead of print]. (http://dx.doi.org/10.1001/archinternmed.2010.352)
Kutner NG et al. Patient awareness and initiation of peritoneal dialysis. Arch Intern Med 2010 Sep 27; [e-pub ahead of print]. (http://dx.doi.org/10.1001/archinternmed.2010.361)
Johansen KL. Choice of dialysis modality in the United States. Arch Intern Med 2010 Sep 27; [e-pub ahead of print]. (http://dx.doi.org/10.1001/archinternmed.2010.370)

2010年10月12日 星期二

植物為主食者比較長壽

Low-Carbohydrate Diets (Plant- vs. Animal-Based) and Mortality
Plant-based low-carb diets were associated with lower all-cause and cardiovascular mortality.

Recent studies have shown equivalence of low-carbohydrate and low-fat diets for weight loss (JW Gen Med Aug 19 2010). In this large prospective study, researchers assessed whether type of low-carb diet — plant-based or animal-based — affects length of life. They used self-reported diet histories gathered during 20-plus years of follow-up in the observational Nurses' Health Study (85,000 women) and the Health Professionals Follow-up Study (44,000 men) to determine whether participants reported a low-carb diet pattern.

The researchers calculated a vegetable low-carbohydrate score for each participant: Compared with those in the lowest decile of vegetable protein and fat intake, those in the highest decile had lower all-cause mortality (hazard ratio, 0.80) and cardiovascular mortality (HR, 0.77) — but not lower cancer mortality (HR, 0.96). Similarly, animal low-carbohydrate scores were calculated: Compared with those in the lowest decile of animal protein and fat intake, those in the highest decile had greater overall mortality (HR, 1.23), cardiovascular mortality (HR, 1.14), and cancer mortality (HR, 1.28). Analyses were adjusted for multiple confounders.

Comment:
This large prospective study suggests that not all low-carbohydrate diets are equal when considering length of life — plant-based diets appear to be superior to animal-based ones. Nonetheless, editorialists remind us of the potential hazards involved in attributing causation using data from observational studies.


Jamaluddin Moloo, MD, MPH
Published in Journal Watch General Medicine October 12, 2010

Citation(s):
Fung TT et al. Low-carbohydrate diets and all-cause and cause-specific mortality: Two cohort studies. Ann Intern Med 2010 Sep 7; 153:289. (http://www.annals.org/content/153/5/289.abstract)
Yancy WS Jr et al. Animal, vegetable, or . . . clinical trial? Ann Intern Med 2010 Sep 7; 153:337. (http://www.annals.org/content/153/5/337.extract)