Van Doren Hsu

The frequency of hyperkalemia and its significance in chronic kidney disease.

BACKGROUND Hyperkalemia is a potential threat to patient safety in chronic kidney disease (CKD). This study determined the incidence of hyperkalemia in CKD and whether it is associated with excess mortality. METHODS This retrospective analysis of a national cohort comprised 2 103 422 records from 245 808 veterans with at least 1 hospitalization and at least 1 inpatient or outpatient serum potassium record during the fiscal year 2005. Chronic kidney disease and treatment with angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blockers (blockers of the renin-angiotensin-aldosterone system [RAAS]) were the key predictors of hyperkalemia. Death within 1 day of a hyperkalemic event was the principal outcome. RESULTS Of the 66 259 hyperkalemic events (3.2% of records), more occurred as inpatient events (n = 34 937 [52.7%]) than as outpatient events (n = 31 322 [47.3%]). The adjusted rate of hyperkalemia was higher in patients with CKD than in those without CKD among individuals treated with RAAS blockers (7.67 vs 2.30 per 100 patient-months; P < .001) and those without RAAS blocker treatment (8.22 vs 1.77 per 100 patient-months; P < .001). The adjusted odds ratio (OR) of death with a moderate (potassium, >or=5.5 and <6.0 mEq/L [to convert to mmol/L, multiply by 1.0]) and severe (potassium, >or=6.0 mEq/L) hyperkalemic event was highest with no CKD (OR, 10.32 and 31.64, respectively) vs stage 3 (OR, 5.35 and 19.52, respectively), stage 4 (OR, 5.73 and 11.56, respectively), or stage 5 (OR, 2.31 and 8.02, respectively) CKD, with all P < .001 vs normokalemia and no CKD. CONCLUSIONS The risk of hyperkalemia is increased with CKD, and its occurrence increases the odds of mortality within 1 day of the event. These findings underscore the importance of this metabolic disturbance as a threat to patient safety in CKD.

Frequency of Hypoglycemia and Its Significance in Chronic Kidney Disease

BACKGROUND AND OBJECTIVES This study set out to determine the incidence of hypoglycemia in patients with chronic kidney disease (CKD), with and without diabetes, and the association of hypoglycemia with mortality. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a retrospective cohort analysis of 243,222 patients who had 2,040,206 glucose measurements and were cared for at the Veterans Health Administration. CKD was defined as an estimated GFR of <60 ml/min per 1.73 m(2). Hypoglycemia was set at <70 mg/dl. Mortality was measured 1 day after glucose measurement. RESULTS The incidence of hypoglycemia was higher in patients with CKD versus without CKD. Among patients with diabetes, the rate was 10.72 versus 5.33 per 100 patient-months and among patients without diabetes was 3.46 versus 2.23 per 100 patient-months, for CKD versus no CKD, respectively. The odds of 1-d mortality were increased at all levels of hypoglycemia but attenuated in CKD versus no CKD. Adjusted odds ratios for 1-d mortality that were associated with glucose values of <50, 50 to 59, and 60 to 69 mg/dl, respectively, versus glucose of >or=70 mg/dl were 6.09, 4.10, and 1.85 for inpatient records from patients with CKD; 9.95, 3.79, and 2.54 for inpatients records from patients without CKD; 6.84, 3.28, and 3.98 for outpatient records from patients with CKD; and 13.28, 7.36, and 4.34 for outpatient records from patients without CKD. CONCLUSIONS CKD is a risk for hypoglycemia, with or without diabetes. The excessive mortality associated with hypoglycemia makes this complication a significant threat to patient safety in CKD.

Adherence Feedback to Improve Asthma Outcomes Among Inner-City Children: A Randomized Trial

OBJECTIVE: We evaluated the longitudinal effects of home-based asthma education combined with medication adherence feedback (adherence monitoring with feedback [AMF]) and asthma education alone (asthma basic care [ABC]) on asthma outcomes, relative to a usual-care (UC) control group. METHODS: A total of 250 inner-city children with asthma (mean age: 7 years; 62% male; 98% black) were recruited from a pediatric emergency department (ED). Health-outcome measures included caregiver-frequency of asthma symptoms, ED visits, hospitalizations, and courses of oral corticosteroids at baseline and 6-, 12-, and 18-month assessments. Adherence measures included caregiver-reported adherence to inhaled corticosteroid (ICS) therapy and pharmacy records of ICS refills. Multilevel modeling was used to examine the differential effects of AMF and ABC compared with UC. RESULTS: ED visits decreased more rapidly for the AMF group than for the UC group, but no difference was found between the ABC and UC groups. The AMF intervention led to short-term improvements in ICS adherence during the active-intervention phase relative to UC, but this improvement decreased over time. Asthma symptoms and courses of corticosteroids decreased more rapidly for the ABC group than for the UC group. Hospitalization rates did not differ between either intervention group and the UC group. No differences were found between the ABC and AMF groups on any outcome. CONCLUSIONS: Asthma education led to improved adherence and decreased morbidity compared with UC. Home-based educational interventions may lead to modest short-term improvements in asthma outcomes among inner-city children. Adherence feedback did not improve outcomes over education alone.

Chronic Kidney Disease Adversely Influences Patient Safety

Reducing medical errors and improving patient safety have become a national priority. Patients with chronic kidney disease (CKD) may be at higher risk for adverse consequences of medical care, but few studies have evaluated this question. Here, data for patients hospitalized in the Veterans Health Administration during 2004 to 2005 was analyzed to conduct a cross-sectional study of CKD and adverse safety events. Outcomes included 13 patient safety indicators (PSI) defined by the Agency for Healthcare Research and Quality and six experimental PSI relevant to CKD. The 71,666 (29%) hospitalized veterans with CKD had a higher risk for several PSI, even after case-mix adjustment. Among surgical hospitalizations, CKD was associated with increased risk for hip fracture, physiologic/metabolic derangements, and complications of anesthesia. Among all acute hospitalizations, the PSI with the highest risk in patients with CKD were infection as a result of medical care and death among those in diagnosis-related groups normally associated with low mortality. Furthermore, as preadmission estimated GFR decreased, a significant trend of increasing risk for all PSI was observed (P = 0.001). In conclusion, hospitalized patients with CKD are at increased risk for adverse safety events, measured by established PSI. Further investigation is needed to develop and test interventions to reduce this risk.

CKD as an Underrecognized Threat to Patient Safety

Chronic kidney disease (CKD) is common, but underrecognized, in patients in the health care system, where improving patient safety is a high priority. Poor disease recognition and several other features of CKD make it a high-risk condition for adverse safety events. In this review, we discuss the unique attributes of CKD that make it a high-risk condition for patient safety mishaps. We point out that adverse safety events in this disease have the potential to contribute to disease progression; namely, accelerated loss of kidney function and increased incidence of end-stage renal disease. We also propose a framework in which to consider patient safety in CKD, highlighting the need for disease-specific safety indicators that reflect unsafe practices in the treatment of this disease. Finally, we discuss the hypothesis that increased recognition of CKD will reduce disease-specific safety events and in this way decrease the likelihood of adverse outcomes, including an accelerated rate of kidney function loss and increased incidence of end-stage renal disease.

Erythropoiesis-stimulating agents increase the risk of acute stroke in patients with chronic kidney disease.

Erythropoiesis-stimulating agents (ESAs) are effective in ameliorating anemia in chronic kidney disease (CKD). A recent trial in diabetic patients with CKD, however, suggested a greater risk of stroke associated with full correction of anemia with ESAs. Using national Veterans Affairs data we performed a case-control study examining the association of incident ESA use with acute stroke in patients with estimated glomerular filtration rate < 60 cm³/min per 1.73 m² and outpatient hemoglobin <12 g/dl. Using diagnosis codes, we identified 2071 acute hospitalized stroke cases and matched them 1:5 with controls without stroke, resulting in 12,426 total patients for analysis. Conditional logistic regression was used to estimate the association of ESA use with stroke, adjusting for potential confounders. After multivariate adjustment, ESA use in 1026 patients was associated with greater odds of stroke (odds ratio 1.30). There was significant interaction between ESA use and cancer, with greater odds of stroke among ESA-treated cancer patients (odds ratio 1.85), but not in ESA-treated patients without cancer (odds ratio 1.07). ESA-treated patients with cancer received a median initial dose 2.5-4 times greater than ESA-treated patients without cancer, but pre-ESA hemoglobin and its rate of change did not differ between these groups. Hence, in a large national sample of anemic patients with CKD, ESA treatment was associated with an increased risk of acute stroke with the greatest effect among patients with cancer.

Center Effects in Anemia Management of Dialysis Patients

This study set out to determine whether there is a center effect on anemia management in hemodialysis patients. The US Renal Data System and Medicare standard analysis files were analyzed. Between-center variation and within-facility correlations in hematocrit values were examined in two separate data sets (years 2000 and 2001) and compared with simulated samples that were composed of random values that assumed no center effect. Mixed-effect models were used to adjust for multiple factors and quantify the within-facility correlation in hematocrit values. Expected hematocrit values were compared in patients who underwent dialysis at poor and superior performing facilities with fixed characteristics including epoetin alpha dosing. There was a wider center variation in hematocrit for the actual versus simulated data and a coefficient of variation of 4.1% for the former versus 1.7% for the latter, in both years. The within-facility correlation for hematocrit was 0.053 (95% confidence interval 0.050 to 0.056; P < 0.001) in 2000 with similar values in 2001 but no within-facility correlation in the simulated data. The impact of these findings was demonstrated with a difference in expected hematocrit for a patient who was treated with fixed-dosage epoetin alpha in the poorest versus best performing units (mean difference in expected hematocrit 3.06; 95% confidence interval 3.03 to 3.09; P < 0.001). Key attributes of a center effect on anemia management in hemodialysis have been identified. The presence of a center effect suggests that there are facility-specific processes that influence performance in dialysis anemia management and are independent of commonly titrated inputs, such as dosing of erythropoietic agents.

Pharmacy Fill Patterns in Young Urban Children with Persistent Asthma

Background. Medication adherence impacts healthcare utilization. Pharmacy records are useful to establish fill patterns. Objective. Use pharmacy records to establish medication patterns fill patterns for comparison to healthcare utilization. Methods. Pharmacy records of 175 children with persistent asthma were collected and compared to healthcare utilization. Results. Majority of subjects had significant healthcare utilization, low numbers of rescue medications, and poor controller medication fill rates. Those with more rescue medications had more healthcare utilization and more controller medications. Conclusions. Pharmacy fill patterns demonstrate few rescue and/or controller medication fills. Those with more rescue medications reported increased healthcare utilization despite controller medications.

Validation of a method for identifying nursing home admissions using administrative claims

BackgroundCurrently there is no standard algorithm to identify whether a subject is residing in a nursing home from administrative claims. Our objective was to develop and validate an algorithm that identifies nursing home admissions at the resident-month level using the MarketScan Medicare Supplemental and Coordination of Benefit (COB) database.MethodsThe computer algorithms for identifying nursing home admissions were created by using provider type, place of service, and procedure codes from the 2000 – 2002 MarketScan Medicare COB database. After the algorithms were reviewed and refined, they were compared with a detailed claims review by an expert reviewer. A random sample of 150 subjects from the claims was selected and used for the validity analysis of the algorithms. Contingency table analysis, comparison of mean differences, correlations, and t-test analyses were performed. Percentage agreement, sensitivity, specificity, and Kappa statistics were analyzed.ResultsThe computer algorithm showed strong agreement with the expert review (99.9%) for identification of the first month of nursing home residence, with high sensitivity (96.7%), specificity (100%) and a Kappa statistic of 0.97. Weighted Pearson correlation coefficient between the algorithm and the expert review was 0.97 (p < 0.0001).ConclusionA reliable algorithm indicating evidence of nursing home admission was developed and validated from administrative claims data. Our algorithm can be a useful tool to identify patient transitions from and to nursing homes, as well as to screen and monitor for factors associated with nursing home admission and nursing home discharge.

Prescription fill patterns in underserved children with asthma receiving subspecialty care

BACKGROUND Children with asthma receiving specialty care have been found to have improved asthma outcomes. However, these outcomes can be adversely affected by poor adherence with controller medications. OBJECTIVE To analyze pharmacy fill patterns as a measure of primary adherence in a group of underserved minority children receiving allergy subspecialty care. METHODS As part of a larger 18-month nebulizer use study in underserved children (ages 2-8 years) with persistent asthma, 53 children were recruited from an urban allergy practice. Pharmacy records were compared with prescribing records for all asthma medications. RESULTS Allergist controller prescriptions were written in 30-day quantities with refills and short-acting β-agonists (SABAs) with no refills. Only 49.1% of inhaled corticosteroid (ICS), 49.5% of combination ICS and long-acting β-agonist, and 64.5% of leukotriene modifier (LTM) initial and refill prescriptions were ever filled during the 18-month period. A mean of 5.1 refills (range, 0-14) for SABAs were obtained during 18 months, although only 1.28 SABA prescriptions were prescribed by the allergist. Mean times between first asthma prescription and actual filling were 30 days (range, 0-177 days) for ICSs, 26.6 days (range, 0-156 days) for LTMs, and 16.8 days (range, 0-139 days) for SABAs. CONCLUSION Underserved children with asthma receiving allergy subspecialty care suboptimally filled controller prescriptions, yet filled abundant rescue medications from other prescribers. Limiting albuterol prescriptions to one canister without additional refills may provide an opportunity to monitor fill rates of both rescue and controller medications and provide education to patients about appropriate use of medications to improve adherence.