Weight loss and outcomes in wait-listed, medically managed, and surgically treated patients enrolled in a population-based Bariatric program: prospective cohort study.

BACKGROUND: Multidisciplinary bariatric care is increasingly being delivered in Canada within publicly funded regional programs. Demand is high, wait lists are long, and clinical effectiveness is unknown. OBJECTIVE: To examine the "real-world" outcomes associated with a publicly funded, population-based regional bariatric (medical and surgical) program. RESEARCH DESIGN: Prospective observational cohort. SUBJECTS: Five hundred consecutive patients (150 wait-listed, 200 medically treated, 150 surgically treated) from the Edmonton Weight Wise program were enrolled. MEASURES: The primary outcome was weight change (kg). Between-group changes were analyzed using multivariable regression adjusted for age, sex, and baseline weight and "last-observation-carried-forward" was used for missing data. Subjects transitioning between groups (wait-list to medical or medical to surgery) were censored when crossing over. RESULTS: At baseline, mean age was 43.7 ± 9.6 years, mean body mass index was 47.9 ± 8.1 kg/m, and 88% were female. A total of 412 subjects (82%) completed 2-year follow-up and 143 (29%) subjects crossed over to the next treatment phase. Absolute and relative (% of baseline) mean weight reductions were 1.5 ± 8.5 kg (0.9 ± 6.1%) for wait-listed, 4.1 ± 11.6 kg (2.8 ± 8.1%) for medically treated, and 22.0 ± 19.7 kg (16.3 ± 13.5%) for surgically treated (P<0.001) subjects. For surgery, weight reductions were 7.0 ± 9.7 kg (5.8 ± 7.9%) with banding, 21.4 ± 16.0 kg (16.4 ± 11.6%) with sleeve gastrectomy, and 36.6 ± 19.5 kg (26.1 ± 12.2%) with gastric bypass (P<0.001). Rates of hypertension, diabetes, and dyslipidemia decreased to a significantly greater degree with surgery than medical management (P<0.001) and stayed the same or increased in wait-listed subjects. CONCLUSIONS: Population-based bariatric care, particularly bariatric surgery, was clinically effective. Weight and cardiometabolic risk was relatively stable wait-listed patients receiving "usual care."

Effect of gastric bypass surgery on azithromycin oral bioavailability.

OBJECTIVES: Azithromycin is used widely for community-acquired infections. The timely administration of azithromycin in adequate doses minimizes treatment failure. Gastric bypass, a procedure that circumvents the upper gut, may compromise azithromycin plasma levels. We hypothesized that azithromycin concentrations would be reduced following gastric bypass. METHODS: A single-dose pharmacokinetic study in 14 female post-gastric bypass patients and 14 sex- and body mass index (BMI)-matched controls (mean age 44 years and BMI 36.4 kg/m(2)) was performed. Subjects were administered two 250 mg azithromycin tablets at time 0 and plasma azithromycin levels were sampled at 0.5, 1, 1.5, 2, 3, 5, 7 and 24 h. The AUC of the plasma azithromycin concentrations from time 0 to 24 h (AUC(0-24)) was the primary outcome. RESULTS: Azithromycin concentrations were lower in gastric bypass patients compared with controls throughout the entire duration of sampling. Compared with controls, the AUC(0-24) was reduced in gastric bypass subjects by 32% [1.41 (SD 0.51) versus 2.07 (0.75) mg ·â€Šh/L; P = 0.008], and dose-normalized AUC(0-24) was reduced by 33% [0.27 (0.12) versus 0.40 (0.13) kg ·â€Šh/L; P = 0.009]. Peak azithromycin concentrations were 0.260 (0.115) in bypass subjects versus 0.363 (0.200) mg/L in controls (P = 0.08), and were reached at 2.14 (0.99) h in gastric bypass subjects and 2.36 (1.17) h in controls (P = 0.75). CONCLUSIONS: Azithromycin AUC was reduced by one-third in gastric bypass subjects compared with controls. The potential for early treatment failure exists, and dose modification and/or closer clinical monitoring of gastric bypass patients receiving azithromycin should be considered.

The Alberta population-based prospective evaluation of the quality of life outcomes and economic impact of bariatric surgery (APPLES) study: background, design and rationale.

BACKGROUND: Extreme obesity affects nearly 8% of Canadians, and is debilitating, costly and ultimately lethal. Bariatric surgery is currently the most effective treatment available; is associated with reductions in morbidity/mortality, improvements in quality of life; and appears cost-effective. However, current demand for surgery in Canada outstrips capacity by at least 1000-fold, causing exponential increases in already protracted, multi-year wait-times. The objectives and hypotheses of this study were as follows: 1. To serially assess the clinical, economic and humanistic outcomes in patients wait-listed for bariatric care over a 2-year period. We hypothesize deterioration in these outcomes over time; 2. To determine the clinical effectiveness and changes in quality of life associated with modern bariatric procedures compared with medically treated and wait-listed controls over 2 years. We hypothesize that surgery will markedly reduce weight, decrease the need for unplanned medical care, and increase quality of life; 3. To conduct a 3-year (1 year retrospective and 2 year prospective) economic assessment of bariatric surgery compared to medical and wait-listed controls from the societal, public payor, and health-care payor perspectives. We hypothesize that lower indirect, out of pocket and productivity costs will offset increased direct health-care costs resulting in lower total costs for bariatric surgery. METHODS/DESIGN: Population-based prospective cohort study of 500 consecutive, consenting adults, including 150 surgically treated patients, 200 medically treated patients and 150 wait-listed patients. Subjects will be enrolled from the Edmonton Weight Wise Regional Obesity Program (Edmonton, Alberta, Canada), with prospective bi-annual follow-up for 2 years. Mixed methods data collection, linking primary data to provincial administrative databases will be employed. Major outcomes include generic, obesity-specific and preference-based quality of life assessment, patient satisfaction, patient utilities, anthropometric indices, cardiovascular risk factors, health care utilization and direct and indirect costs. DISCUSSION: The results will identify the spectrum of potential risks associated with protracted wait times for bariatric care and will quantify the economic, humanistic and clinical impact of surgery from the Canadian perspective. Such information is urgently needed by health-service providers and policy makers to better allocate use of finite resources. Furthermore, our findings should be widely-applicable to other publically-funded jurisdictions providing similar care to the extremely obese. TRIAL REGISTRATION: Clinicaltrials.gov NCT00850356.

Income status and approval for bariatric surgery in a publicly funded regional obesity program.

BACKGROUND: Bariatric surgery has emerged as an effective and safe treatment for severe obesity and utilization rates have increased dramatically. In private health care settings, low socioeconomic status is associated with a reduced likelihood of undergoing a bariatric procedure. Whether this relationship is also present in a universally accessible, publicly funded health care system is not currently known. METHODS: A retrospective analysis of the Edmonton Weight Wise obesity program clinical registry was conducted. Patients who were unemployed, on long-term disability or receiving social assistance were classified as "low income" status. The remaining patients were categorized as "regular income" status. Multivariable logistic regression analysis was used to examine the association between low income status and approval for surgery within 1 year of program entry. RESULTS: Thirty-three (7%) of 419 patients were ineligible for surgery or excluded because of missing income status data. Of the remaining 386 patients, 72 (19%) were of low income status and 89 (23%) were approved for surgery. Low income patients were older, heavier, and had greater comorbidity. Compared to patients of regular income status, those with low income status were less likely to be approved for surgery (15.3% versus 24.8%; adjusted OR 0.45; 95% CI 0.22 to 0.94). CONCLUSIONS: Within a publicly funded and universally accessible regional obesity program, lower income status patients were less likely to be approved for bariatric surgery. Further study is necessary to clarify this apparent disparity and to determine if program modifications are necessary to ensure equity across all socioeconomic strata.

Effect of gastric bypass surgery on the absorption and bioavailability of metformin.

OBJECTIVE: Use of gastric bypass surgery is common and increasing. Over 40% of patients in diabetes remission after gastric bypass surgery may redevelop diabetes within 5 years. Metformin, the first-line drug for diabetes, has low bioavailability and slow, incomplete gastrointestinal absorption. We hypothesized that gastric bypass would further reduce the absorption and bioavailability of metformin. RESEARCH DESIGN AND METHODS: In a nonblinded, single-dose pharmacokinetic study, 16 nondiabetic post-gastric bypass patients and 16 sex- and BMI-matched control subjects (mean age 40 years and BMI 39.2 kg/m(2)) were administered two 500-mg metformin tablets. Plasma metformin levels were sampled at 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 24 h. Metformin absorption, estimated by the area under the curve (AUC) of the plasma drug concentrations from time 0 to infinity (AUC(0-∞)), was the primary outcome, and metformin bioavailability, assessed by measuring 24-h urine metformin levels, was a secondary outcome. RESULTS: Compared with control subjects, metformin AUC(0-∞) was increased in gastric bypass subjects by 21% (13.7 vs. 11.4 µg/mL/h; mean difference 2.3 [95% CI -1.3 to 5.9]) and bioavailability was increased by 50% (41.8 vs. 27.8%; 14.0 [4.1-23.9]). Gastric bypass patients had significantly lower AUC glucose levels over 8 h compared with control subjects (35.8 vs. 41.7 µg/mL/h; 5.9 [3.1-8.8]), but this was likely a result of differences in baseline fasting glucose and not metformin absorption. CONCLUSIONS: Metformin absorption and bioavailability seem to be higher after gastric bypass, and this may have implications on dosing and toxicity risk. Studies are needed to confirm these findings and delineate potential mechanisms.