Browsing by Author "Fischer, Heidi"

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    Bariatric Surgery and Risk of Death in Persons With Chronic Kidney Disease
    (Wolters Kluwer, 2022) Coleman, Karen J.; Shu, Yu-Hsiang; Fischer, Heidi; Johnson, Eric; Yoon, Tae K.; Taylor, Brianna; Imam, Talha; DeRose, Stephen; Haneuse, Sebastien; Herrinton, Lisa J.; Fisher, David; Li, Robert A.; Theis, Mary Kay; Liu, Liyan; Courcoulas, Anita P.; Smith, David H.; Arterburn, David E.; Friedman, Allon N.; Medicine, School of Medicine
    Objective: A retrospective cohort study investigated the association between having surgery and risk of mortality for up to 5 years and if this association was modified by incident ESRD during the follow-up period. Summary of Background Data: Mortality risk in individuals with pre-dialysis CKD is high and few effective treatment options are available. Whether bariatric surgery can improve survival in people with CKD is unclear. Methods: Patients with class II and III obesity and pre-dialysis CKD stages 3-5 who underwent bariatric surgery between January 1, 2006 and September 30, 2015 (n = 802) were matched to patients who did not have surgery (n = 4933). Mortality was obtained from state death records and ESRD was identified through state-based or healthcare system-based registries. Cox regression models were used to investigate the association between bariatric surgery and risk of mortality and if this was moderated by incident ESRD during the follow-up period. Results: Patients were primarily women (79%), non-Hispanic White (72%), under 65 years old (64%), who had a body mass index > 40kg/m 2 (59%), diabetes (67%), and hypertension (89%). After adjusting for incident ESRD, bariatric surgery was associated with a 79% lower 5-year risk of mortality compared to matched controls (hazard ratio = 0.21; 95% confidence interval: 0.14-0.32; P < 0.001). Incident ESRD did not moderate the observed association between surgery and mortality (hazard ratio = 1.59; 95% confidence interval: 0.31-8.23; P =0.58). Conclusions: Bariatric surgery is associated with a reduction in mortality in pre-dialysis patients regardless of developing ESRD. These findings are significant because patients with CKD are at relatively high risk for death with few efficacious interventions available to improve survival.
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    The relationship between kidney function and body mass index before and after bariatric surgery in patients with chronic kidney disease
    (Elsevier, 2021) Fischer, Heidi; Weiss, Robert E.; Friedman, Allon N.; Imam, Talha H.; Coleman, Karen J.; Medicine, School of Medicine
    Background: Improvements in kidney function post-bariatric surgery may be related to weight loss-independent effects. Objectives: To characterize the dynamic relationship between body mass index (BMI) and estimated glomerular filtration rate (eGFR) before and after bariatric surgery in patients with chronic kidney disease (CKD). Setting: Kaiser Permanente Southern California (KPSC) health system. Methods: We conducted an observational, retrospective cohort study of patients with CKD stage 3 or higher who received bariatric surgery at the KPSC health system between 2007-2015. Bariatric surgery procedures included primary Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) procedures. Outcomes consisted of mean trajectory estimates and correlations of BMI and eGFR taken between 2 years before and 3 years after surgery. Multivariate functional mixed models were used to estimate how BMI and eGFR trajectories evolved jointly. Results: A total of 619 RYGB and 474 SG patients were included in the final analytic sample. The measurements were available before surgery for a median time of 1.9 years for SG and 1.8 years for RYGB patients. Median follow-up times after surgery were 2.8 years for both SG and RYGB patients. The mean age at the time of surgery was 58 years; 77% of patients were women; 56% of patients were non-Hispanic White; the mean BMI was 44 kg/m2; 60% of patients had diabetes mellitus; and 84% of patients had hypertension. Compared to the presurgery eGFR declines, the postsurgery declines in eGFR were 57% slower (95% credible interval [CrI], 33%-81%) for RYGB patients and 55% slower (95% CrI, 25%-75%) for SG patients. The mean correlation between BMI and eGFR was negligible at all time points. Conclusion: Though bariatric surgery slowed declines in eGFR up to 3 years after surgery, changes in eGFR tracked poorly with changes in BMI. This study provides evidence that the kidney-related benefits of bariatric surgery may be at least partly independent of weight loss. Confirming this hypothesis could lead to mechanistic insights and new treatment options for CKD.