Impact of Prior Abdominal Procedures on Peritoneal Dialysis Catheter Outcomes: Findings From the North American Peritoneal Dialysis Catheter Registry.

RATIONALE & OBJECTIVE: A history of prior abdominal procedures may influence the likelihood of referral for peritoneal dialysis (PD) catheter insertion. To guide clinical decision making in this population, this study examined the association between prior abdominal procedures and outcomes in patients undergoing PD catheter insertion. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Adults undergoing their first PD catheter insertion between November 1, 2011, and November 1, 2020, at 11 institutions in Canada and the United States participating in the International Society for Peritoneal Dialysis North American Catheter Registry. EXPOSURE: Prior abdominal procedure(s) defined as any procedure that enters the peritoneal cavity. OUTCOMES: The primary outcome was time to the first of (1) abandonment of the PD catheter or (2) interruption/termination of PD. Secondary outcomes were rates of emergency room visits, hospitalizations, and procedures. ANALYTICAL APPROACH: Cumulative incidence curves were used to describe the risk over time, and an adjusted Cox proportional hazards model was used to estimate the association between the exposure and primary outcome. Models for count data were used to estimate the associations between the exposure and secondary outcomes. RESULTS: Of 855 patients who met the inclusion criteria, 31% had a history of a prior abdominal procedure and 20% experienced at least 1 PD catheter-related complication that led to the primary outcome. Prior abdominal procedures were not associated with an increased risk of the primary outcome (adjusted HR, 1.12; 95% CI, 0.68-1.84). Upper-abdominal procedures were associated with a higher adjusted hazard of the primary outcome, but there was no dose-response relationship concerning the number of procedures. There was no association between prior abdominal procedures and other secondary outcomes. LIMITATIONS: Observational study and cohort limited to a sample of patients believed to be potential candidates for PD catheter insertion. CONCLUSION: A history of prior abdominal procedure(s) does not appear to influence catheter outcomes following PD catheter insertion. Such a history should not be a contraindication to PD. PLAIN-LANGUAGE SUMMARY: Peritoneal dialysis (PD) is a life-saving therapy for individuals with kidney failure that can be done at home. PD requires the placement of a tube, or catheter, into the abdomen to allow the exchange of dialysis fluid during treatment. There is concern that individuals who have undergone prior abdominal procedures and are referred for a catheter might have scarring that could affect catheter function. In some institutions, they might not even be offered PD therapy as an option. In this study, we found that a history of prior abdominal procedures did not increase the risk of PD catheter complications and should not dissuade patients from choosing PD or providers from recommending it.

The Association of Intra-Abdominal Adhesions with Peritoneal Dialysis Catheter-Related Complications.

BACKGROUND: This study investigated the association of intra-abdominal adhesions with the risk of peritoneal dialysis (PD) catheter complications. METHODS: Individuals undergoing laparoscopic PD catheter insertion were prospectively enrolled from eight centers in Canada and the United States. Patients were grouped based on the presence of adhesions observed during catheter insertion. The primary outcome was the composite of PD never starting, termination of PD, or the need for an invasive procedure caused by flow restriction or abdominal pain. RESULTS: Seven hundred and fifty-eight individuals were enrolled, of whom 201 (27%) had adhesions during laparoscopic PD catheter insertion. The risk of the primary outcome occurred in 35 (17%) in the adhesion group compared with 58 (10%) in the no adhesion group (adjusted HR, 1.64; 95% confidence interval [CI], 1.05 to 2.55) within 6 months of insertion. Lower abdominal or pelvic adhesions had an adjusted HR of 1.80 (95% CI, 1.09 to 2.98) compared with the no adhesion group. Invasive procedures were required in 26 (13%) and 47 (8%) of the adhesion and no adhesion groups, respectively (unadjusted HR, 1.60: 95% CI, 1.04 to 2.47) within 6 months of insertion. The adjusted odds ratio for adhesions for women was 1.65 (95% CI, 1.12 to 2.41), for body mass index per 5 kg/m 2 was 1.16 (95% CI, 1.003 to 1.34), and for prior abdominal surgery was 8.34 (95% CI, 5.5 to 12.34). Common abnormalities found during invasive procedures included PD catheter tip migration, occlusion of the lumen with fibrin, omental wrapping, adherence to the bowel, and the development of new adhesions. CONCLUSIONS: People with intra-abdominal adhesions undergoing PD catheter insertion were at higher risk for abdominal pain or flow restriction preventing PD from starting, PD termination, or requiring an invasive procedure. However, most patients, with or without adhesions, did not experience complications, and most complications did not lead to the termination of PD therapy.

Quantifying the risk of insertion-related peritoneal dialysis catheter complications following laparoscopic placement: Results from the North American PD Catheter Registry.

BACKGROUND: Peritoneal dialysis (PD) is a more cost-effective therapy to treat kidney failure than in-center hemodialysis, but successful therapy requires a functioning PD catheter that causes minimal complications. In 2015, the North American Chapter of the International Society for Peritoneal Dialysis established the North American PD Catheter Registry to improve practices and patient outcomes following PD catheter insertion. AIMS: The objective of this study is to propose a methodology for defining insertion-related complications that lead to significant adverse events and report the risk of these complications among patients undergoing laparoscopic PD catheter insertion. METHODS: Patients undergoing laparoscopic PD catheter insertion were enrolled at 14 participating centers in Canada and the United States and followed using a Web-based registry. Insertion-related complications were defined as flow restriction, exit-site leak, or abdominal pain at any point during follow-up. We also included infections or bleeding within 30 days of insertion, and any immediate postoperative complications. Adverse events were categorized as PD never starting or termination of PD therapy, delay in the start of PD therapy or interruption of PD therapy, an emergency department visit or hospitalization, or need for invasive procedures. Cause-specific cumulative incidence functions were used to estimate risk. RESULTS: Five hundred patients underwent laparoscopic PD catheter insertion between 10 November 2015 and 24 July 2018. The cumulative risk of insertion-related complications 6 months from the date of insertion that led to an adverse event was 24%. The risk of flow restriction, exit-site leak, and pain at 6 months was 10.2%, 5.7%, and 5.3%, respectively. PD was never started or terminated in 6.4% of patients due to an insertion-related complication. Leaks and flow restrictions were most likely to delay or interrupt PD therapy. Flow restrictions were the primary cause of invasive procedures. Fifty percent of the complications occurred before the start of PD therapy. CONCLUSIONS: Insertion-related complications leading to significant adverse events following laparoscopic placement of PD catheters are common. Many complications occur before the start of PD. Insertion-related complications are an important area of focus for future research and quality improvement efforts.

The WISHED Trial: implementation of an interactive health communication application for patients with chronic kidney disease.

BACKGROUND: Despite many advantages over facility-based therapies, less than 25 % of prevalent dialysis patients in Ontario are on a home therapy. Interactive health communication applications, web-based packages for patients, have been shown to have a beneficial effect on knowledge, social support, self-efficacy, and behavioral and clinical outcomes but have not been evaluated in patients with chronic kidney disease (CKD). Web-based tools designed for patients with CKD exist but to our knowledge have not been assessed in their ability to influence dialysis modality decision-making. OBJECTIVE: To determine if a web-based tool increases utilization of a home-based therapy in patients with CKD starting dialysis. DESIGN: This is a multi-centered randomized controlled study. SETTING: Participants will be recruited from sites in Canada. PARTICIPANTS: Two hundred and sixty-four consenting patients with an estimated glomerular filtration rate (eGFR) less than 20 ml/min/1.73 m(2) who have received modality education will be enrolled in the study. MEASUREMENTS: The primary outcome will be the proportion of participants who are on dialysis using a home-based therapy within 3 months of dialysis initiation. Secondary outcomes will include the proportion of patients intending to perform a home-based modality and measures of dialysis knowledge, decision conflict, and social support. METHODS: The between-group differences in frequencies will be expressed as either absolute risk differences and/or by calculating the odds ratio and its associated 95 % confidence interval. CONCLUSIONS: This study will assess whether access to a website dedicated to supporting and promoting home-based dialysis therapies will increase the proportion of patients with CKD who initiate a home-based dialysis therapy. TRIAL REGISTRATION: ClinicalTrials.gov #NCT01403454, registration date: July 21, 2011.

MISE EN CONTEXTE: L'administration de traitements d'hémodialyse à domicile présente plusieurs avantages par rapport aux traitements offerts en centre hospitalier. Pourtant, moins de 25 % des patients Ontariens suivent leurs traitements de dialyse à domicile. Bien que l'accès à des outils interactifs de communication en santé (OICS) ait des effets bénéfiques sur le niveau de connaissances, le soutien social, le niveau d'autonomie ainsi que sur les résultats cliniques et comportementaux des patients qui les utilisent, ces outils n'ont jamais fait l'objet d'études chez les patients atteints d'insuffisance rénale chronique (IRC). Des OICS existent pour cette population, mais on ne connaît pas leur part d'influence au moment où le patient doit faire le choix d'une technique de dialyse. OBJECTIFS DE L'ÉTUDE: Par cette étude, on entend vérifier si l'accès à des outils sur le web augmentera le nombre de patients atteints d'IRC en amorce d'une dialyse qui choisiront d'effectuer leurs traitements à domicile. CADRE ET TYPE D'ÉTUDE: Il s'agit d'un essai contrôlé, randomisé, qui se tiendra dans plusieurs centres hospitaliers à travers le Canada. PARTICIPANTS: La cohorte sera constituée de 264 patients atteints d'IRC dont le taux de filtration glomérulaire se situe à moins de 20 ml/min/1, 73 m2. Les participants auront suivi une séance d'orientation pour les aider à naviguer dans les différents outils mis à leur disposition sur le web. MESURES: À titre de résultat principal, on établira la proportion de patients qui auront adhéré à la technique de dialyse à domicile au cours des trois mois suivant l'initiation du traitement. On cherchera ensuite à connaître la proportion de patients ayant l'intention de le faire au courant de la première année de traitement. De plus, on procèdera à l'évaluation des connaissances et de la capacité des patients de prendre des décisions concernant leur traitement, ainsi que du soutien social qu'ils reçoivent. MÉTHODOLOGIE: Les différences entre les groupes d'étude seront exprimées soit sur le plan du risque absolu ou en calculant les rapports de cotes et les intervalles de confiance à 95 % correspondants. CONCLUSION: Cette étude évaluera si l'accès à un site web consacré au soutien social des patients et à la promotion des traitements de dialyse à domicile augmentera la proportion de patients souffrant d'IRC qui choisiront cette option pour l'amorce de leur traitement.

Improving Care after Acute Kidney Injury: A Prospective Time Series Study.

BACKGROUND: Acute kidney injury (AKI) complicates 15-20% of hospitalizations, and AKI survivors are at increased risk of chronic kidney disease and death. However, less than 20% of patients see a nephrologist within 3 months of discharge, even though a nephrologist visit within 90 days of discharge is associated with enhanced survival. To address this, we established an AKI Follow-Up Clinic and characterized the patterns of care delivered. METHODS: We conducted a prospective time series study. All hospitalized patients who developed Kidney Disease Improving Global Outcomes (KDIGO) stage 2 or 3 AKI were eligible. The pre-intervention period consisted of electronic reminders to the nephrology consults and cardiovascular surgery services to refer to the AKI Follow-Up Clinic. In the post-intervention period, eligible patients were automatically scheduled into the AKI Follow-Up Clinic at discharge. The primary outcome was the percentage of KDIGO stages 2-3 AKI survivors assessed by a nephrologist within 30 days of discharge. RESULTS: In the pre-intervention period, 8 of 46 patients (17%) were seen by a nephrologist within 30 days after discharge, and no additional patients were seen for 90 days. In the post-intervention period, 17 of 69 patients (25%) were seen by a nephrologist within 30 days after discharge (p = 0.36), with an additional 30 patients seen in 90 days (47 of 69, 68%, p < 0.001). The mean serum creatinine was 99 (SD 35) µmol/l prior to hospitalization and 133 (58) µmol/l at 3 months. Fifty-five of 79 patients (70%) received at least 1 medical intervention at their first AKI Follow-Up Clinic visit. CONCLUSIONS: An AKI Follow-Up Clinic with an automatic referral process increased the proportion of patients seen at 90 days, but not 30 days post discharge. Being seen in the AKI Follow-Up Clinic was associated with interventions in most patients. Future research is needed to evaluate the effect of the AKI Follow-Up Clinic on patient-centered outcomes, but physicians should be aware that AKI survivors may benefit from close outpatient follow-up and a multipronged approach to care similarly for other high-risk populations.

Peritoneal dialysis catheter implantation by nephrologists is associated with higher rates of peritoneal dialysis utilization: a population-based study.

BACKGROUND: The likelihood of peritoneal dialysis (PD) utilization following a PD catheter insertion attempt is poorly described. We explored the risk factors for PD nonuse, focusing on the method of PD catheter implantation. METHODS: This population-based retrospective cohort study employed Ontario administrative health data to identify 3886 predialysis adults who had an incident PD catheter implantation between 2002 and 2010. The impact of the method of catheter implantation including open-surgical (open, n = 1884), surgical-laparoscopic (laparoscopic, n = 1154), nephrology-percutaneous (nephrology, n = 498) and radiology-percutaneous (radiology, n = 350) on rates of PD utilization (defined as four consecutive weeks of PD) was examined. RESULTS: Eighty-three percent of study patients received PD. After adjustment, relative to patients with openly inserted catheters, PD utilization was greater for those with nephrology-inserted catheters [adjusted hazard ratio (aHR) 1.59, 95% confidence interval (CI) 1.29-1.95] and similar for radiology-inserted catheters [aHR 1.16, 95% CI 0.94-1.43] or laparoscopic-inserted catheters [aHR 0.97 (95% CI 0.86-1.09)]. Among PD nonusers, death occurred in 10% of the open group, 6% of the laparoscopic group, 27% of the radiology group and in fewer than 3% of the nephrology group. Sixty-nine percent received hemodialysis in the open group, 63% in the laparoscopic group, 61% in the radiology group and 88% in the nephrology group. Those remaining predialysis comprised 12% of the open group, 22% of the laparoscopic group, 11% of the radiology group and <3% of the nephrology group. CONCLUSIONS: Nephrology insertion resulted in lower overall rates of PD nonuse, particularly due to death or remaining predialysis. Greater use may be related to insertion timing, technique or greater commitment on the part of nephrologists to the success of PD.

Association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use prior to major elective surgery and the risk of acute dialysis.

BACKGROUND: Some studies but not others suggest angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use prior to major surgery associates with a higher risk of postoperative acute kidney injury (AKI) and death. METHODS: We conducted a large population-based retrospective cohort study of patients aged 66 years or older who received major elective surgery in 118 hospitals in Ontario, Canada from 1995 to 2010 (n = 237,208). We grouped the cohort into ACEi/ARB users (n = 101,494) and non-users (n = 135,714) according to whether the patient filled at least one prescription for an ACEi or ARB (or not) in the 120 days prior to surgery. Our study outcomes were acute kidney injury treated with dialysis (AKI-D) within 14 days of surgery and all-cause mortality within 90 days of surgery. RESULTS: After adjusting for potential confounders, preoperative ACEi/ARB use versus non-use was associated with 17% lower risk of post-operative AKI-D (adjusted relative risk (RR): 0.83; 95% confidence interval (CI): 0.71 to 0.98) and 9% lower risk of all-cause mortality (adjusted RR: 0.91; 95% CI: 0.87 to 0.95). Propensity score matched analyses provided similar results. The association between ACEi/ARB and AKI-D was significantly modified by the presence of preoperative chronic kidney disease (CKD) (P value for interaction < 0.001) with the observed association evident only in patients with CKD (CKD - adjusted RR: 0.62; 95% CI: 0.50 to 0.78 versus No CKD: adjusted RR: 1.00; 95% CI: 0.81 to 1.24). CONCLUSIONS: In this cohort study, preoperative ACEi/ARB use versus non-use was associated with a lower risk of AKI-D, and the association was primarily evident in patients with CKD. Large, multi-centre randomized trials are needed to inform optimal ACEi/ARB use in the peri-operative setting.

Hyponatremia and sodium picosulfate bowel preparations in older adults.

OBJECTIVES: Bowel preparations are commonly prescribed drugs. Case reports and our clinical experience suggest that sodium picosulfate bowel preparations can precipitate severe hyponatremia in some older adults. At present, this risk is poorly quantified. We investigated the association between sodium picosulfate use and the risk of hyponatremia in older adults. METHODS: We conducted a population-based retrospective cohort study using six linked administrative databases in Ontario, Canada. All Ontario residents over the age of 65 years who filled an outpatient bowel preparation prescription before colonoscopy were eligible. We enrolled new users of either sodium picosulfate (n=99,237) or polyethylene glycol (n=48,595). The primary outcome was hospitalization with hyponatremia within 30 days of the bowel preparation assessed by database codes. The secondary outcomes were hospitalization with urgent head computed tomography (CT) (a proxy for acute central nervous system disturbance) and all-cause mortality. RESULTS: The baseline characteristics of the two groups, including patient demographics, comorbid conditions, and concomitant medications, were nearly identical. Compared with polyethylene glycol, sodium picosulfate was associated with a higher risk of hospitalization with hyponatremia (absolute risk increase: 0.05%, 95% confidence interval (CI): 0.04-0.06%, relative risk (RR): 2.4, 95% CI: 1.5-3.9), but not hospitalization with urgent CT head (RR: 1.1, 95% CI: 0.7-1.4) or mortality (RR: 0.9, 95% CI: 0.7-1.3). CONCLUSIONS: Sodium picosulfate bowel preparations lead to more hyponatremia than polyethylene glycol. There was no evidence of increased risk of acute neurologic symptoms or mortality. The absolute increase in risk of hospitalization with hyponatremia remains low but may be avoidable through appropriate fluid intake or preferential use of polyethylene glycol in some older adults.

Complications of daytime elective laparoscopic cholecystectomies performed by surgeons who operated the night before.

IMPORTANCE: The effect of surgeons' disrupted sleep on patient outcomes is not clearly defined. OBJECTIVE: To assess if surgeons operating the night before have more complications of elective surgery performed the next day. DESIGN, SETTING, AND PARTICIPANTS: Population-based, matched, retrospective cohort study using administrative health care databases in Ontario, Canada (2012 population, 13,505,900). Participants were 2078 patients who underwent elective laparoscopic cholecystectomies performed by surgeons who operated the night before, matched with 4 other elective laparoscopic cholecystectomy recipients (n = 8312). EXPOSURE: In total, 94,183 eligible elective laparoscopic cholecystectomies were performed between 2004 and 2011. Of these surgeries, there were 2078 procedures in which 331 different surgeons across 102 community hospitals had operated between midnight and 7 am the night before. Each "at-risk" surgery was randomly matched with 4 other elective laparoscopic cholecystectomies (n = 8312) performed by the same surgeon, who had no evidence of having operated the night before. MAIN OUTCOMES AND MEASURES: The primary outcome was conversion from a laparoscopic cholecystectomy to open cholecystectomy. Secondary outcomes included evidence of iatrogenic injuries or death. Risks were quantified using generalized estimating equations. RESULTS: No significant association was found in conversion rates to open operations between surgeons when they operated the night before compared with when they did not operate the previous night (46/2031 [2.2%] vs 157/8124 [1.9%]; adjusted odds ratio [OR], 1.18; 95% CI, 0.85-1.64). There was no association between operating the night before vs not operating the night before, and risk of iatrogenic injuries (14/2031 [0.7%] vs 72/8124 [0.9%]; adjusted OR, 0.77; 95% CI, 0.43-1.37) or death (≤5/2031 [≤0.2%] vs 7/8124 [0.1%]). CONCLUSIONS AND RELEVANCE: No significant association was found between operating the night before and not operating the previous night for conversion to open cholecystectomy, risk of iatrogenic complications, or death for elective daytime cholecystectomy. These findings do not support safety concerns related to surgeons operating the night before performing elective surgery.

Secular trends in acute dialysis after elective major surgery--1995 to 2009.

BACKGROUND: Acute kidney injury is a serious complication of elective major surgery. Acute dialysis is used to support life in the most severe cases. We examined whether rates and outcomes of acute dialysis after elective major surgery have changed over time. METHODS: We used data from Ontario's universal health care databases to study all consecutive patients who had elective major surgery at 118 hospitals between 1995 and 2009. Our primary outcomes were acute dialysis within 14 days of surgery, death within 90 days of surgery and chronic dialysis for patients who did not recover kidney function. RESULTS: A total of 552,672 patients underwent elective major surgery during the study period, 2231 of whom received acute dialysis. The incidence of acute dialysis increased steadily from 0.2% in 1995 (95% confidence interval [CI] 0.15-0.2) to 0.6% in 2009 (95% CI 0.6-0.7). This increase was primarily in cardiac and vascular surgeries. Among patients who received acute dialysis, 937 died within 90 days of surgery (42.0%, 95% CI 40.0-44.1), with no change in 90-day survival over time. Among the 1294 patients who received acute dialysis and survived beyond 90 days, 352 required chronic dialysis (27.2%, 95% CI 24.8-29.7), with no change over time. INTERPRETATION: The use of acute dialysis after cardiac and vascular surgery has increased substantially since 1995. Studies focusing on interventions to better prevent and treat perioperative acute kidney injury are needed.

Dipstick proteinuria as a screening strategy to identify rapid renal decline.

Rapid kidney function decline (RKFD) predicts cardiovascular morbidity and mortality, but serial assessment of estimated GFR (eGFR) is not cost-effective for the general population. Here, we evaluated the predictive value of albuminuria and three thresholds of dipstick proteinuria to identify RKFD in 2,574 participants in a community-based prospective cohort study with a median of 7 years follow-up. Median change in eGFR was -0.78 ml/min per 1.73 m(2) per year; with 8.5% experiencing RKFD, defined as a >5% annual eGFR decline from baseline. Of those with RKFD, 65% advanced to a new CKD stage compared with 19% of those without RKFD. Dipstick protein ≥ 1 g/L was a stronger predictor of RKFD than albuminuria. Overall, 2.5% screened positive for dipstick protein ≥ 1 g/L at baseline; one of every 2.6 patients would have RKFD if all were followed with serial eGFR measurement. Overall, the screening strategy correctly identified progression status for 90.8% of patients, mislabeled 1.5% as RKFD, and missed 7.7% with eventual RKFD. Among those with risk factors (cardiovascular disease, age >60, diabetes, or hypertension), the probability of identifying RKFD from serial eGFR measurements increased from 13 to 44% after incorporating dipstick protein (≥ 1 g/L threshold). In summary, inexpensive screening with urine dipstick should allow primary care physicians to follow fewer patients with serial eGFR assessment but still identify those with rapid decline of kidney function.

Statin use associates with a lower incidence of acute kidney injury after major elective surgery.

Statins abrogate ischemic renal injury in animal studies but whether they are renoprotective in humans is unknown. We conducted a population-based retrospective cohort study that included 213,347 older patients who underwent major elective surgery in the province of Ontario, Canada from 1995 to 2008. During the first 14 postoperative days, 1.9% (4020 patients), developed acute kidney injury and 0.5% (1173 patients), required acute dialysis. The 30-day mortality rate was 2.8% (5974 patients). Prior to surgery, 32% of patients were taking a statin. After statistical adjustment for patient and surgical characteristics, statin use associated with 16% lower odds of acute kidney injury (OR, 0.84; 95% CI, 0.79 to 0.90), 17% lower odds of acute dialysis (OR, 0.83; 95% CI, 0.72 to 0.95), and 21% lower odds of mortality (OR, 0.79; 95% CI, 0.74 to 0.85). Propensity score matching produced similar results. These data suggest that statins may protect against renal complications after major elective surgery and reduce perioperative mortality.

Impaired renal function modifies the risk of severe hypoglycaemia among users of insulin but not glyburide: a population-based nested case-control study.

BACKGROUND: Little evidence justifies the avoidance of glyburide in patients with impaired renal function. We aimed to determine if renal function modifies the risk of hypoglycaemia among patients using glyburide. METHODS: We conducted a nested case-control study using administrative records and laboratory data from Ontario, Canada. We included outpatients 66 years of age and older with diabetes mellitus and prescriptions for glyburide, insulin or metformin. We ascertained hypoglycaemic events using administrative records and estimated glomerular filtration rates (eGFR) using serum creatinine concentrations. RESULTS: From a cohort of 19,620 patients, we identified 204 cases whose eGFR was ≥ 60 mL/min/1.73 m(2) (normal renal function) and 354 cases whose eGFR was < 60 mL/min/1.73 m(2) (impaired renal function). Compared to metformin, glyburide is associated with a greater risk of hypoglycaemia in patients with both normal [adjusted odds ratio (OR) 9.0, 95% confidence interval (95% CI) 4.9-16.4] and impaired renal function (adjusted OR 6.0, 95% CI 3.8-9.5). We observed a similar relationship when comparing insulin to metformin; the risk was greater in patients with normal renal function (adjusted OR 18.7, 95% CI 10.5-33.5) compared to those with impaired renal function (adjusted OR 7.9, 95% CI 5.0-12.4). Tests of interaction showed that among glyburide users, renal function did not significantly modify the risk of hypoglycaemia, but among insulin users, impaired renal function is associated with a lower risk. CONCLUSIONS: In this population-based study, impaired renal function did not augment the risk of hypoglycaemia associated with glyburide use.

Beta-blockers, trimethoprim-sulfamethoxazole, and the risk of hyperkalemia requiring hospitalization in the elderly: a nested case-control study.

BACKGROUND AND OBJECTIVES: The simultaneous use of beta adrenergic receptor blockers (beta-blockers) and trimethoprim-sulfamethoxazole (TMP-SMX) may confer a high risk of hyperkalemia. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Two nested case-control studies were conducted to examine the association between hospitalization for hyperkalemia and the use of TMP-SMX in older patients receiving beta-blockers. Linked health administrative records from Ontario, Canada, were used to assemble a cohort of 299,749 beta-blockers users, aged 66 years or older and capture data regarding medication use and hospital admissions for hyperkalemia. RESULTS: Over the study period from 1994 to 2008, 189 patients in this cohort were hospitalized for hyperkalemia within 14 days of receiving a study antibiotic. Compared with amoxicillin, the use of TMP-SMX was associated with a substantially greater risk of hyperkalemia requiring hospital admission (adjusted odds ratio, 5.1; 95% confidence interval [CI], 2.8 to 9.4). No such risk was identified with ciprofloxacin, norfloxacin, or nitrofurantoin. When dosing was considered, the association was greater at higher doses of TMP-SMX. When the primary analysis was repeated in a cohort of non-beta-blocker users, the risk of hyperkalemia comparing TMP-SMX to amoxicillin was not significantly different from that found among beta-blocker users. CONCLUSIONS: Although TMP-SMX is associated with an increased risk of hyperkalemia in older adults, these findings show no added risk when used in combination with beta-blockers.