The BMI Paradox and Robotic Assisted Partial Nephrectomy

Obesity, defined by a body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) of 30.0 or more, is associated with an increased risk of death, but the relation between overweight (a BMI of 25.0 to 29.9) and the risk of death has been questioned. We prospectively examined BMI in relation to the risk of death from any cause in 527,265 U.S. men and women in the National Institutes of Health-AARP cohort who were 50 to 71 years old at enrollment in 1995-1996. BMI was calculated from self-reported weight and height. Relative risks and 95 percent confidence intervals were adjusted for age, race or ethnic group, level of education, smoking status, physical activity, and alcohol intake. We also conducted alternative analyses to address potential biases related to preexisting chronic disease and smoking status. During a maximum follow-up of 10 years through 2005, 61,317 participants (42,173 men and 19,144 women) died. Initial analyses showed an increased risk of death for the highest and lowest categories of BMI among both men and women, in all racial or ethnic groups, and at all ages. When the analysis was restricted to healthy people who had never smoked, the risk of death was associated with both overweight and obesity among men and women. In analyses of BMI during midlife (age of 50 years) among those who had never smoked, the associations became stronger, with the risk of death increasing by 20 to 40 percent among overweight persons and by two to at least three times among obese persons; the risk of death among underweight persons was attenuated. Excess body weight during midlife, including overweight, is associated with an increased risk of death. Copyright 2006 Massachusetts Medical Society.

The extent to which moderate overweight (body mass index [BMI], 25.0-29.9 [calculated as weight in kilograms divided by height in meters squared]) and obesity (BMI, >/= 30.0) are associated with increased risk of coronary heart disease (CHD) through adverse effects on blood pressure and cholesterol levels is unclear, as is the risk of CHD that remains after these mediating effects are considered. Relative risks (RRs) of CHD associated with moderate overweight and obesity with and without adjustment for blood pressure and cholesterol concentrations were calculated by the members of a collaboration of prospective cohort studies of healthy, mainly white persons and pooled by means of random-effects models (RRs for categories of BMI in 14 cohorts and for continuous BMI in 21 cohorts; total N = 302 296). A total of 18 000 CHD events occurred during follow-up. The age-, sex-, physical activity-, and smoking-adjusted RRs (95% confidence intervals) for moderate overweight and obesity compared with normal weight were 1.32 (1.24-1.40) and 1.81 (1.56-2.10), respectively. Additional adjustment for blood pressure and cholesterol levels reduced the RR to 1.17 (1.11-1.23) for moderate overweight and to 1.49 (1.32-1.67) for obesity. The RR associated with a 5-unit BMI increment was 1.29 (1.22-1.35) before and 1.16 (1.11-1.21) after adjustment for blood pressure and cholesterol levels. Adverse effects of overweight on blood pressure and cholesterol levels could account for about 45% of the increased risk of CHD. Even for moderate overweight, there is a significant increased risk of CHD independent of these traditional risk factors, although confounding (eg, by dietary factors) cannot be completely ruled out.

Laparoscopic partial nephrectomy is an increasingly performed, minimally invasive alternative to open partial nephrectomy. We compared early postoperative outcomes in 1,800 patients undergoing open partial nephrectomy by experienced surgeons with the initial experience with laparoscopic partial nephrectomy in patients with a single renal tumor 7 cm or less. Data on 1,800 consecutive open or laparoscopic partial nephrectomies were collected prospectively or retrospectively in tumor registries at 3 large referral centers. Demographic, intraoperative, postoperative and followup data were compared between the 2 groups. Compared to the laparoscopic partial nephrectomy group of 771 patients the 1,028 undergoing open partial nephrectomy were a higher risk group with a greater percent presenting symptomatically with decreased performance status, impaired renal function and tumor in a solitary functioning kidney (p<0.0001). More tumors in the open partial nephrectomy group were more than 4 cm and centrally located and more proved to be malignant (p<0.0001 and 0.0003, respectively). Based on multivariate analysis laparoscopic partial nephrectomy was associated with shorter operative time (p<0.0001), decreased operative blood loss (p<0.0001) and shorter hospital stay (p<0.0001). The chance of intraoperative complications was comparable in the 2 groups. However, laparoscopic partial nephrectomy was associated with longer ischemia time (p<0.0001), more postoperative complications, particularly urological (p<0.0001), and an increased number of subsequent procedures (p<0.0001). Renal functional outcomes were similar 3 months after laparoscopic and open partial nephrectomy with 97.9% and 99.6% of renal units retaining function, respectively. Three-year cancer specific survival for patients with a single cT1N0M0 renal cell carcinoma was 99.3% and 99.2% after laparoscopic and open partial nephrectomy, respectively. Early experience with laparoscopic partial nephrectomy is promising. Laparoscopic partial nephrectomy offered the advantages of less operative time, decreased operative blood loss and a shorter hospital stay. When applied to patients with a single renal tumor 7 cm or less, laparoscopic partial nephrectomy was associated with additional postoperative morbidity compared to open partial nephrectomy. However, equivalent functional and early oncological outcomes were achieved.