Predicting decline of kidney function in lupus nephritis using urine biomarkers

OBJECTIVE

To evaluate candidate biomarkers to predict future renal function decline (RFD) in children and adults with lupus nephritis (LN).

METHODS

At the time of enrollment into prospective observational LN cohort studies liver-type fatty acid binding protein (LFABP), albumin, monocyte chemoattractant protein-1 (MCP-1), uromodulin, transferrin, and hepcidin were measured in urine samples of two cohorts of patients with LN, one followed at a pediatric (cohort-1; n = 28) and one at an adult institution (cohort-2; n = 69). The primary outcome was RFD, defined in cohort-1 as a decrease in estimated glomerular filtration rate (eGFR) of ≥20% and in cohort-2 as a sustained increase of ≥25% in serum creatinine concentration (SCr), both from baseline.

RESULTS

All patients (n = 97) had normal eGFR or SCr at the time of urine collection at baseline. RFD occurred in 29% (8/28) of patients in cohort-1 during a mean follow-up of 6.1 months, and in 30% (21/69) of those in cohort-2 during a mean follow-up of 60 months. Individually, in cohort-1, levels of MCP-1, transferrin, LFABP, and albumin were higher in the RFD group than those who maintained renal function, with statistical significance for LFABP and albumin. In cohort-2 the RFD group also had higher levels of urine MCP-1 and albumin than others. The combination of LFABP, MCP-1, albumin, and transferrin had good predictive accuracy for RFD in both cohorts (area under the ROC curve = 0.77-0.82).

CONCLUSION

The combinatorial urine biomarker LFABP, MCP-1, albumin, and transferrin shows promise as a predictor of renal functional decline in LN, and warrants further investigation.

Mortality and cardiovascular disease among older live kidney donors

Over the past two decades, live kidney donation by older individuals (≥55 years) has become more common. Given the strong associations of older age with cardiovascular disease (CVD), nephrectomy could make older donors vulnerable to death and cardiovascular events. We performed a cohort study among older live kidney donors who were matched to healthy older individuals in the Health and Retirement Study. The primary outcome was mortality ascertained through national death registries. Secondary outcomes ascertained among pairs with Medicare coverage included death or CVD ascertained through Medicare claims data. During the period from 1996 to 2006, there were 5717 older donors in the United States. We matched 3368 donors 1:1 to older healthy nondonors. Among donors and matched pairs, the mean age was 59 years; 41% were male and 7% were black race. In median follow-up of 7.8 years, mortality was not different between donors and matched pairs (p = 0.21). Among donors with Medicare, the combined outcome of death/CVD (p = 0.70) was also not different between donors and nondonors. In summary, carefully selected older kidney donors do not face a higher risk of death or CVD. These findings should be provided to older individuals considering live kidney donation.

Transplantation of kidneys from donors at increased risk for blood-borne viral infection: recipient outcomes and patterns of organ use

Kidney transplantation from deceased donors classified as increased risk for viral infection by the Centers for Disease Control (CDC) is controversial. Analyses of Organ Procurement and Transplantation Network (OPTN) data from 7/1/2004 to 7/1/2006 were performed. The primary cohort included 48 054 adults added to the kidney transplant wait list. Compared to receiving a standard criteria donor (SCD) kidney or remaining wait-listed, CDC recipients (HR 0.80, p = 0.18) had no significant difference in mortality. In a secondary cohort of 19 872 kidney recipients at 180 centers, SCD (reference) and CDC (HR 0.91, p = 0.16) recipients had no difference in the combined endpoint of allograft failure or death. Among centers performing >10 kidney transplants during the study period, the median proportion of CDC transplants/total transplants was 7.2% (range 1.1-35.6%). Higher volume transplant centers were more likely to use CDC kidneys compared to low and intermediate volume centers (p < 0.01). An analysis of procured kidneys revealed that 6.8% of SCD versus 7.8% of CDC (p = 0.13) kidneys were discarded. In summary, center use of CDC kidneys varied widely, and recipients had good short-term outcomes. OPTN should collect detailed data about long-term outcomes and recipient viral testing so the potential risks of CDC kidneys can be fully evaluated.

Substantial variation in the acceptance of medically complex live kidney donors across US renal transplant centers

Concern exists about accepting live kidney donation from 'medically complex donors'--those with risk factors for future kidney disease. This study's aim was to examine variation in complex kidney donor use across US transplant centers. We conducted a retrospective cohort study of live kidney donors using organ procurement and transplantation network data. Donors with hypertension, obesity or estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) were considered medically complex. Among 9319 donors, 2254 (24.2%) were complex: 1194 (12.8%) were obese, 956 (10.3%) hypertensive and 392 (4.2%) had low eGFR. The mean proportion of medically complex donors at a center was 24% (range 0-65%). In multivariate analysis, donor characteristics associated with medical complexity included spousal relationship to the recipient (OR 1.29, CI 1.06-1.56, p < 0.01), low education (OR 1.19, CI 1.04-1.37, p = 0.01), older age (OR 1.01 per year, CI 1.01-1.02, p < 0.01) and non-US citizenship (OR 0.70, CI 0.51-0.97, p = 0.03). Renal transplant centers with the highest transplant volume (OR 1.26, CI 1.02-1.57, p = 0.03), and with a higher proportion of (living donation)/(all kidney transplants) (OR 1.97, CI 1.23-3.16, p < 0.01) were more likely to use medically complex donors. Though controversial, the use of medically complex donors is widespread and varies widely across centers.

Substantial variation in the acceptance of medically complex live kidney donors across US renal transplant centers

Concern exists about accepting live kidney donation from 'medically complex donors'--those with risk factors for future kidney disease. This study's aim was to examine variation in complex kidney donor use across US transplant centers. We conducted a retrospective cohort study of live kidney donors using organ procurement and transplantation network data. Donors with hypertension, obesity or estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) were considered medically complex. Among 9319 donors, 2254 (24.2%) were complex: 1194 (12.8%) were obese, 956 (10.3%) hypertensive and 392 (4.2%) had low eGFR. The mean proportion of medically complex donors at a center was 24% (range 0-65%). In multivariate analysis, donor characteristics associated with medical complexity included spousal relationship to the recipient (OR 1.29, CI 1.06-1.56, p < 0.01), low education (OR 1.19, CI 1.04-1.37, p = 0.01), older age (OR 1.01 per year, CI 1.01-1.02, p < 0.01) and non-US citizenship (OR 0.70, CI 0.51-0.97, p = 0.03). Renal transplant centers with the highest transplant volume (OR 1.26, CI 1.02-1.57, p = 0.03), and with a higher proportion of (living donation)/(all kidney transplants) (OR 1.97, CI 1.23-3.16, p < 0.01) were more likely to use medically complex donors. Though controversial, the use of medically complex donors is widespread and varies widely across centers.

Assessment of differences in HLA-A, -B, and -DRB1 allele mismatches among African-American and non-African-American recipients of deceased kidney transplants

Among recipients of deceased donor kidney transplants, African-Americans experience a more rapid rate of kidney allograft loss than non-African-Americans. The purpose of this study was to characterize and quantify the HLA-A, -B, and -DRB1 allele mismatches and amino acid substitutions at antigen recognition sites among African-American and non-African-American recipients of deceased donor kidney transplants matched at the antigen level. In recipients with zero HLA antigen mismatches, the degree of one or two HLA allele mismatches for both racial groups combined was 47%, 29%, and 11% at HLA-DRB1, HLA-B, and HLA-A, respectively. There was a greater number of allele mismatches in African-Americans than non-African-Americans at HLA-A (P < .0001), -B (P = .096), and -DRB1 loci (P < .0001). For both racial groups, the HLA allele mismatches were predominantly at A2 for HLA-A; B35 and B44 for HLA-B; but multiple specificities for HLA-DRB1. The observed amino acid mismatches were concentrated at a few functional positions in the antigen binding site of HLA-A and -B and -DRB1 molecules. Future studies are ongoing to assess the impact of these HLA mismatches on kidney allograft loss.

Adverse neurologic events associated with rebound hypertension after using short-acting nifedipine in childhood hypertension

INTRODUCTION

Short-acting nifedipine (SA-NIF) is widely prescribed for acute hypertension (HTN) in children despite reports of ischemic complications in adults. We describe two children with neurologic events caused by rebound hypertension following SA-NIF use.

CASES

Patient 1 is a 7-year-old with acute nephritis and blood pressure (BP) of 185/130. She received SA-NIF which decreased BP to 114/79. When BP rebounded to 160/103, she developed severe cortical visual impairment. Head CT demonstrated edema and petechial hemorrhages in the watershed region. Patient 2 is a 10-year-old renal transplant recipient who received SA-NIF for a BP of 155/98, which resulted in a prompt decrease to 114/74. Two hours later he developed aphasia and right-sided neglect. His BP increased to 168/88 and he developed partial complex seizures. Brain MRI showed high signal intensity in the watershed areas with early gadolinium enhancement.

DISCUSSION

The temporal association of the neurologic events with the rebound increase in BP suggests a possible role for the SA-NIF, consistent with its pharmacokinetic profile. Although the adult literature has focused on the unpredictable decline in BP after SA-NIF treatment, these cases suggest that rapid increases in BP following the maximal SA-NIF effect may be associated with impaired cerebral autoregulation and encephalopathy in children. These cases underscore the need for frequent blood pressure determinations and therapy to prevent rebound hypertension.

Prevalence and determinants of erectile dysfunction in hemodialysis patients

BACKGROUND

The prevalence of erectile dysfunction (ED) among patients with end-stage renal disease (ESRD) is not known.

METHODS

A cross-sectional study was conducted to determine the prevalence of ED among a community-based hemodialysis (HD) population using a two-stage cluster random sampling design. The presence and severity of ED were assessed among 302 ESRD patients using the self-administered International Index of Erectile Function-5 (IIEF-5). Logistic regression was used to examine and test associations between ED and other medical conditions.

RESULTS

The prevalence of any level of ED was 82% (95% CI, 76 to 87%) for all HD subjects. The prevalence of severe ED was 45% (CI, 36 to 55%). Subjects younger than 50 years had a prevalence of ED of 63% (CI, 53 to 71%), while in subjects 50 years or older, it was 90% (CI, 84 to 94%). A multivariable analysis demonstrated increasing age (50 to 59, OR = 2.04, 95% CI, 1.3 to 3.1; 60 to 69, OR = 5.5, 95% CI, 1.9 to 15.6) and diabetes (OR = 2.0, 95% CI, 1.2 to 3.3) to be independently associated with the presence of any level of ED. However, neither the subjects' age nor history of diabetes predicted the severity of ED among subjects with ED. The use of angiotensin-converting enzyme inhibitors (ACEIs) was inversely associated with ED (OR = 0.41, 95% CI, 0.17 to 0.98). Poor functional status (Karnofsky score or the Index of Physical Impairment) was not associated with ED.

CONCLUSIONS

ED is extremely prevalent among HD patients. Increasing age, diabetes, and nonuse of ACEIs were associated with higher prevalence of ED. The high prevalence of ED was seen even among patients with good functional status.

Testing the reliability of old and new features of a new electronic monitor for metered dose inhalers

BACKGROUND

Poor adherence to treatment regimens is hypothesized to be, in part, responsible for the extensive morbidity and mortality associated with asthma. Electronic monitors are the most accurate means available for measuring adherence, but their use has been limited by reports questioning the reliability and validity of their data.

OBJECTIVE

To test the reliability and accuracy of the MDILog (Medtrac Technologies, Lakewood, CO), a new electronic monitor of metered dose inhalers (MDIs), and to test its unique features.

METHODS

Brief experiments were performed comparing a written diary to the electronic record using three MDILogs. The following features were studied: reporting of time and date of an actuation, recording of the occurrence of an actuation of the MDI, sensing and timing of inhalations, sensing of shaking of the MDI canister, and recording of multiple actuations.

RESULTS

Clocking was accurate 100% of the time. Actuation agreed with the paper record 97% to 100%, inhalation 82% to 100%, shaking 86% to 95%. Agreement of late inhalations and multiple actuations with paper records was at least 98%.

CONCLUSIONS

The MDILog yields accurate information and is more reliable than previously described monitors. Its new features allow more detailed study of how patients use inhalers by allowing evaluation of how patients inhale and whether they shake the inhaler canister before use.

Effect of the use or nonuse of long-term dialysis on the subsequent survival of renal transplants from living donors

BACKGROUND

The effect on allograft survival of the transplantation of kidneys from living donors without the previous initiation of long-term dialysis is controversial.

METHODS

Using data from the U.S. Renal Data System, we performed a retrospective cohort study of 8481 patients who were or who were not treated by long-term dialysis before receiving a kidney transplant from a living donor. The relative rate of allograft failure for patients who received a transplant without previously undergoing long-term dialysis, as compared with patients who underwent long-term dialysis before transplantation, was assessed by proportional-hazards analysis, with adjustment for potential confounding variables, including the transplantation center and median household income. The association between the receipt of a kidney transplant from a living donor without previous dialysis ("preemptive transplantation") and the risk of biopsy-confirmed acute rejection within six months after transplantation was evaluated by conditional logistic-regression analysis, with adjustment for the transplantation center.

RESULTS

Transplantation of a kidney from a living donor without previous long-term dialysis was associated with a 52 percent reduction in the risk of allograft failure during the first year after transplantation (rate ratio, 0.48; P=0.002), an 82 percent reduction during the second year (rate ratio, 0.18; P=0.001), and an 86 percent reduction during subsequent years (rate ratio, 0.14; P=0.001), as compared with transplantation after dialysis. The reduction in the rate of allograft failure during the first year was attenuated when adjustment was made for the timing of acute rejection within the first year (rate ratio, 0.69; 95 percent confidence interval, 0.44 to 1.10; P=0.10). Increasing duration of dialysis was associated with increasing odds of rejection within six months after transplantation (P=0.001).

CONCLUSIONS

Preemptive transplantation of kidneys from living donors without the previous initiation of dialysis is associated with longer allograft survival than transplantation performed after the initiation of dialysis.

Preliminary observations of sildenafil treatment for erectile dysfunction in dialysis patients

Erectile dysfunction is common in dialysis patients. We report our experience with sildenafil citrate in patients undergoing dialysis therapy. Male subjects attending the Outpatient Dialysis Unit at the University of Pennsylvania (Philadelphia, PA) who were prescribed sildenafil by their primary physician or nephrologist were asked to complete the International Index of Erectile Function before their first dose of sildenafil and after at least 4 weeks of therapy. Subjects' mean age was 50.3 +/- 14.63 (SD) years. Ninety-three percent of the subjects were black. Based on a global efficacy question, 66.7% of the subjects believed that treatment had improved their erections. Subjects reported no increase in the sexual desire domain despite experiencing a significant increase in erectile function, orgasmic function, and satisfaction with intercourse. Sildenafil was well tolerated in a selected group of patients who reported improved sexual function with no major adverse effects.

Dialyzer reuse: an evolving search for efficiency

The evolution of dialyzer reuse in the United States provides an opportunity to examine the dialysis community's response to changing financial conditions and incentives. As background, we provide a conceptual framework to explain the factors governing the diffusion of dialysis technologies and then describe the clinical context in which reuse programs have developed. Early in its evolution, dialyzer reuse arose principally from the desire to reduce costs under a system of capitated payments. More recently, despite evidence of an adverse health effect, cost-savings from reuse have permitted the adoption of new and expensive technologies. The net effect of the tradeoff's between cost and quality should, ideally, drive the decision to reuse dialyzers. However, even if such tradeoffs can be fully characterized, incentives to implement efficiencies created by capitated systems of payment will continue to influence practice.

Arterial hypertension and renal allograft survival

CONTEXT

Several observational studies have investigated the significance of hypertension in renal allograft failure; however, these studies have been complicated by the lack of adjustment for baseline renal function, leaving the role of elevated blood pressure in allograft failure unclear.

OBJECTIVE

To examine the relationship between blood pressure adjusted for renal function and survival after cadaveric allograft transplantation.

DESIGN

Nonconcurrent historical cohort study conducted from 1985 through 1997.

SETTING

University teaching hospital.

PARTICIPANTS

A total of 277 patients aged 18 years or older who underwent cadaveric renal transplantation without another simultaneous organ transplantation and whose allograft was functioning for a minimum of 1 year. Follow-up continued through 1997 (mean follow-up, 5.7 years).

MAIN OUTCOME MEASURE

Time to allograft failure (defined as death, return to dialysis, or retransplantation) by systolic, diastolic, and mean arterial blood pressure measurements at 1 year after transplantation.

RESULTS

Multivariate Cox proportional hazards modeling demonstrated that nonwhite ethnicity, history of acute rejection, and nondiabetic kidney disease were significant predictors of failure (P = .01 for all). In addition, the calculated creatinine clearance at 1 year had an adjusted rate ratio (RR) for allograft failure per 10 mL/min (0.17 mL/s) of 0.74 (95% confidence interval [CI], 0.62-0.88). The RR per 10-mm Hg increase in blood pressure measured at 1 year after transplantation, after adjustment for creatinine clearance, was 1.15 (95% CI, 1.02-1.30) for systolic pressure, 1.27 (95% CI, 1.01-1.60) for diastolic pressure, and 1.30 (95% CI, 1.05-1.61) for mean arterial pressure. Supplemental analyses that did not include death as a failure event or reduce the minimum allograft survival time for study subjects to 6 months yielded results consistent with the primary analysis. There was no evidence of modification of the blood pressure-allograft failure relationship by ethnicity or diabetes mellitus.

CONCLUSIONS

Systolic, diastolic, and mean arterial blood pressures at 1 year posttransplantation strongly predict allograft survival adjusted for baseline renal function. More aggressive control of blood pressure may prolong cadaveric allograft survival.

Association of dialyzer reuse and hospitalization rates among hemodialysis patients in the US

OBJECTIVES

To determine if reuse of hemodialyzers is associated with higher rates of hospitalization and their resulting costs among end-stage renal disease (ESRD) patients.

METHODS

Noncurrent cohort study of hospitalization rates among 27,264 ESRD patients beginning hemodialysis in the United States in 1986 and 1987.

RESULTS

Dialysis in free-standing facilities reprocessing dialyzers was associated with a greater rate of hospitalization than in facilities not reprocessing (relative rate (RR) = 1.08, 95% confidence interval (CI), 1.02-1.14). This higher rate of hospitalization was observed with dialyzer reuse using peracetic/acetic acids (RR = 1.11, CI 1. 04-1.18) and formaldehyde (RR = 1.07, CI 1.00-1.14), but not glutaraldehyde (p = 0.97). There was no difference among hospitalization rates in hospital-based facilities reprocessing dialyzers with any sterilant and those not reprocessing. Hospitalization for causes other than vascular access morbidity in free-standing facilities reusing dialyzers with formaldehyde was not different from hospitalization in facilities not reusing. However, reuse with peracetic/acetic acids was associated with higher rates of hospitalization than formaldehyde (RR = 1.08, CI 1.03-1.15).

CONCLUSIONS

Dialysis in free-standing facilities reprocessing dialyzers with peracetic/acetic acids or formaldehyde was associated with greater hospitalization than dialysis without dialyzer reprocessing. This greater hospitalization accounts for a large increment in inpatient stays in the USA. These findings raise important concerns about potentially avoidable morbidity among hemodialysis patients.

Membranoproliferative glomerulonephritis type I, mixed cryoglobulinemia and lymphoma in the absence of hepatitis C infection

Chronic hepatitis C virus infection has been linked to cryoglobulinemia, membranoproliferative glomerulonephritis, and malignant B-cell lymphoproliferation, suggesting a possible pathogenetic link between these disorders. We report a patient with the latter clinical triad in the absence of hepatitis C infection. We postulate that the persistent and dysregulated immunologic activity associated with chronic antigen stimulation, inflammation and/or B-cell malignancy induces nephritogenic autoantibodies, including cryoglobulins, that produce a similar clinical syndrome in genetically susceptible individuals.

Discrepancies in pediatric bone mineral density reference data: potential for misdiagnosis of osteopenia

OBJECTIVE

To evaluate published pediatric dual-energy x-ray absorptiometry bone mineral density (BMD) reference data by comparing the diagnostic classification of measured BMD in children at risk for osteopenia as healthy or osteopenic according to reference source.

STUDY DESIGN

Spine BMD was measured in 95 children, ages 9 to 15 years, at risk for osteopenia because of childhood disease. The BMD results were converted to age-specific z scores for each of the 5 reference data sets, and the z -score distributions were compared.

RESULTS

Between 11% and 30% of children were classified as osteopenic (z score < -2.0) depending on the reference data set. The 2 sex-specific reference data sets yielded similar diagnostic classification of boys and girls: 10% of boys and 11% to 16% of girls were osteopenic (P =.4). The 3 sex-nonspecific reference data sets classified 9% to 13% of girls and 24% to 44% of boys as osteopenic; the diagnosis of osteopenia was significantly greater in boys (P <.01).

CONCLUSIONS

The use of different published reference data for the assessment of children at risk for osteopenia results in inconsistent diagnostic classification of BMD results. These inconsistencies can be partially attributed to sex-nonspecific reference data that result in misclassification of boys as osteopenic.

Effect of anti-lymphocyte antibody induction therapy on renal allograft survival

Our two meta-analyses show that antilymphocyte antibody induction therapy extends allograft survival when compared to induction therapy with cyclosporine, azathioprine, and prednisone with the majority of the benefit seen during the first 2 years after transplant. The benefit of induction therapy with respect to allograft survival is particularly important among patients with pretransplant panel reactive antibodies greater than 20%. Although our understanding of the role of antilymphocyte antibody induction therapy continues to evolve, these two meta-analyses provide evidence for its use in clinical renal transplantation.

US, CT, and MR evaluation of accessory renal arteries and proximal renal arterial branches

RATIONALE AND OBJECTIVES

The purpose of this study was to compare color Doppler ultrasound (US), computed tomographic (CT) angiography, and magnetic resonance (MR) angiography for the evaluation of accessory renal arteries and proximal branches of the main renal artery.

MATERIALS AND METHODS

Fifty-six subjects who had undergone conventional arteriography of the renal arteries participated in a prospective comparison of Doppler US (45 patients), CT angiography (52 patients), and nonenhanced MR angiography (28 patients). Conventional arteriography depicted 28 accessory renal arteries and 21 proximal branches of the main renal artery within 2 cm of the aorta.

RESULTS

US depicted five of 24 accessory renal arteries seen at arteriography but no proximal arterial branches. CT angiography depicted 24 of 26 accessory renal arteries and 13 of 17 proximal arterial branches, as well as 15 additional accessory renal arteries not seen at conventional arteriography. MR demonstrated 11 of 15 accessory arteries, as well as four additional accessory arteries not seen at conventional arteriography. MR did not depict any of nine proximal arterial branches seen at conventional arteriography.

CONCLUSION

When compared with US or nonenhanced MR angiography, CT is the preferred method for evaluation of accessory renal arteries and proximal branches of the renal artery.

Association of dialyzer reuse with hospitalization and survival rates among U.S. hemodialysis patients: do comorbidities matter?

The objective of this study was to determine whether the associations between reuse of hemodialyzers and higher rates of death and hospitalization persist after adjustment for comorbidity. This was a nonconcurrent cohort study of survival and hospitalization rates among 1491 U.S. chronic hemodialysis patients beginning treatment in 1986 and 1987. The impact of dialyzer reuse was compared across three survival models: an unadjusted model, a "base" model adjusted only for demographics and renal diagnosis, and an "augmented" model additionally adjusted for comorbidities. We found that reuse of dialyzers was associated with a similarly higher rate of death in analyses unadjusted for confounders (relative risk [RR] 1.25, 95% confidence interval [CI] 0.97-1.61), adjusted for demographics and renal diagnosis (RR 1.16, 95% CI 0.96-1.41), and analyses additionally adjusted for comorbidities (RR = 1.25, CI, 1.03, 1.52). Reusing dialyzers was also associated with a greater rate of hospitalization that was stable regardless of adjustment procedures. We conclude that higher rates of death and hospitalization associated with dialyzer reuse persist regardless of adjustment for demographic characteristics or baseline comorbidities. These findings amplify concerns that there exists elevated morbidity among hemodialysis patients treated in facilities that reuse hemodialyzers. Although the association we observed was not confounded by comorbidity, a cause-and-effect relationship between dialyzer reuse and morbidity could not be proved because of the inability to control for aspects of care other than dialyzer reuse.

Potential utility of electronic drug compliance monitoring in measures of adverse outcomes associated with immunosuppressive agents

Poor compliance with prescribed medications limits the effectiveness of many pharmacologic therapies and enhances their potential toxicities. Traditional methods of measuring drug-taking behavior, including direct observation, patient self-report, pill counts, and therapeutic drug level monitoring, all have well-described limitations in validity and interpretability. Electronic medication event monitoring has been used to assess compliance with therapies for hypertension, glaucoma, anemia, and epilepsy, overcoming many problems of traditional approaches. However, no published reports describe the use of electronic monitoring with immunosuppressive agents, despite their increasing use for non-life-threatening conditions and their many dose-dependent toxicities. Transplant recipients are thought to be at particular risk from noncompliance. Therefore, we undertook this study to assess the feasibility of electronically monitoring compliance with immunosuppressive drugs among renal allograft recipients. Twenty-five kidney transplant patients receiving immunosuppressive medications from a single pharmacy were enrolled. Each subject received electronic monitors with their immunosuppressive serum drug refills for cyclosporine and azathioprine. Each subject returned their monitors after the first month of this 2-month study for downloading data. The frequency distribution of interdose intervals were described. Two measures of average non-compliance were calculated for both drugs: the proportion of monitored days that had missed doses, and the proportion of missed doses. Once daily and twice daily regimens of cyclosporine were compared. Concordance in drug compliance between the two drugs was calculated for each subject and averaged over the study population. Twenty-two of 25 subjects missed one or more doses of cyclosporine or azathioprine. Seventeen (68%) subjects never missed four or more consecutive doses. Subjects were non-compliant with cyclosporine on 8.7% of monitored days, and non-compliance with azathioprine on 9.8% of monitored days. Subjects were non-compliant with 6.8% of their cyclosporine doses and 9.8% of their azathioprine doses. Patients were compliant with both drugs on 86.6% of days and were non-compliant with both drugs on 5.1% of days. Subjects were non-compliant with cyclosporine during 5% and 13.2% of monitored days for once and twice daily dosing regimens, respectively. Concordance analysis demonstrated that for 91.7% of days of monitoring, compliance information was identical for both drugs. This study demonstrated the feasibility of electronic medication event monitoring among kidney transplant patients. This methodology represents an important tool for monitoring compliance of immunosuppressive agents essential to their safe and effective use, and should be considered for use in future studies of these drugs and others with substantial dose-dependent toxicity.

Evaluation of low density spine software for the assessment of bone mineral density in children

Pediatric dual-energy X-ray absorptiometry spine scans often cannot be analyzed with standard software due to a failure to identify the bone edges of low density vertebrae. Low density spine (LDS) software improves bone detection compared with standard software. The objective of this study was to compare bone mineral density (BMD) measurements obtained with the standard and LDS software in 27 healthy nonobese, 32 obese, and 41 chronically ill children, ages 2-18 years. Lumbar spine (L1-L4) BMD, measured by standard analysis, ranged from 0.531-1.244 gm/cm2. Reanalysis with the LDS software resulted in a systematic increase (mean +/- SD) in estimated bone area of 17.0+/-5.0%, an increase in bone mineral content of 6.1+/-6.3%, and a mean decrease in BMD of 8.7+/-1.7% (all p < 0.001). This resulted in a mean decrease in BMD Z score of 0.7+/-0.2. Linear regression models, predicting standard BMD from LDS BMD, were fit for the three subject groups (R2 = 0.993-0.995). Small differences in slopes were detected across groups (p = 0.07); LDS BMD predicted higher standard BMD in obese subjects. In conclusion, LDS analysis resulted in a clinically significant decrease in measured BMD. The association between analysis methods was exceptionally high (R2 > 0.99), indicating that LDS BMD accurately predicts standard BMD. Although LDS BMD in obese subjects predicts higher standard BMD results than in nonobese subjects, the small difference is of questionable clinical significance. LDS software is a useful tool for the assessment of BMD in children.

Comparison of Doppler US and CT angiography for evaluation of renal artery stenosis

RATIONALE AND OBJECTIVES

The authors compared Doppler ultrasound (US) with computed tomographic (CT) angiography in the evaluation of stenosis of the main renal artery.

MATERIALS AND METHODS

Fifty-six patients who had undergone conventional angiography of the renal arteries participated in a prospective comparison of Doppler US (45 patients) and CT angiography (52 patients). US evaluation included both the main renal artery and segmental renal arteries.

RESULTS

There were 27 main renal arteries with at least 50% stenosis in 20 patients. In 36 patients, there was no significant stenosis. All cases of main renal artery stenosis detected with Doppler US of the segmental arteries were also identified with Doppler US of the main renal artery. The by-artery sensitivity (63%) of US of the main renal artery was greater than that (33%) of US of the segmental arteries. CT angiography was more sensitive (96%) than Doppler US (63%) in the detection of stenosis, but the specificity of CT (88%) was similar to that of US (89%). The difference in the area under the receiver operating characteristic curve (AUC) between CT (AUC = 0.94) and US (AUC = 0.82) was statistically significant (P = .038).

CONCLUSION

Doppler US of the main renal artery is more sensitive than Doppler US of segmental arteries in the detection of stenosis. CT angiography is more accurate than Doppler US in the evaluation of renal artery stenosis.

Centralization of histocompatibility laboratories: impact on organ allocation efficiency and outcomes of cadaveric renal transplantation

This project was undertaken to determine whether centralization of histocompatibility laboratory services for renal transplants performed within eastern Pennsylvania could improve the efficiency of allograft allocation and short-term allograft function. A nonconcurrent cohort study was performed comparing renal allografts transplanted between September 15, 1993, and September 14, 1994, to those transplanted between September 15, 1994, and September 14, 1995. All allografts were procured and allocated by the Delaware Valley Transplant Program, the organ procurement agency in eastern Pennsylvania. Cold preservation time and delayed allograft function were used to measure efficiency of allograft allocation and short term allograft function, respectively. The mean cold preservation time was reduced from 25.08 hours to 20.68 hours (P < 0.001). The percentage of delayed allograft function was 19.9 and 17.4 for the pre- and postcentralization groups, respectively (P = 0.5). Therefore, centralization of histocompatibility tissue typing was a regionally effective process intervention for reducing cold preservation time without adversely impacting short-term graft function. The magnitude of this reduction varied between individual centers. Further investigation is required to determine the effect on long-term allograft function and system wide costs.

The effect of antilymphocyte induction therapy on renal allograft survival. A meta-analysis of individual patient-level data. Anti-Lymphocyte Antibody Induction Therapy Study Group

PURPOSE

Randomized, controlled trials have not shown that the perioperative use of antilymphocyte antibodies (induction therapy) improves survival of cadaveric kidney allografts. This study combined individual patient-level data from published trials to examine the effect of induction therapy on allograft survival.

DATA SOURCES

Randomized, controlled trials identified from MEDLINE.

STUDY SELECTION

Published trials that compared adult recipients of cadaveric renal allografts who did and did not receive antilymphocyte antibodies in the perioperative period were selected if individual patient-level data were available.

DATA EXTRACTION AND ANALYSIS

Individual patient-level data were collected for each of 628 study patients. Multivariable Cox proportional hazards regression was used to estimate the effect of induction therapy on allograft survival.

RESULTS

The adjusted rate ratio for allograft failure with induction therapy compared with conventional therapy was 0.62 (95% CI, 0.43 to 0.90) (P = 0.012) over 2 years and 0.82 (CI, 0.62 to 1.09) (P = 0.17) over 5 years. The effect of induction therapy on allograft survival diminished over time; no benefit overall was seen after 2 years after transplantation (rate ratio, 1.13 [CI, 0.72 to 1.78]) (P > 0.2). Greater HLA-DR mismatch, delayed allograft function, diabetes mellitus in the recipient, African-American ethnicity of the recipient, and presensitization (panel-reactive antibody levels > or = 20%) were significantly associated with allograft failure at 5 years. Among high-risk patients, only those who were presensitized benefited from induction therapy at 2 years (rate ratio, 0.12 [CI, 0.03 to 0.44]) (P = 0.001). Results were similar at 5 years.

CONCLUSIONS

Using individual-level data, this study showed a benefit of induction therapy at 2 years, particularly among presensitized patients. Although the benefit of this therapy subsequently waned, presensitized patients continued to have benefit at 5 years.

Race and delayed kidney allograft function

BACKGROUND

Allograft survival among black recipients is poorer than among whites. Delayed allograft function is associated with a significant reduction in renal allograft survival. The relationship between delayed allograft function and black race is incompletely specified and was the focus of this investigation.

METHODS

A non-concurrent study of 325 recipients of cadaveric allografts followed for the occurrence of delayed allograft function defined as dialysis during the first week following transplantation for the principal analysis. A secondary definition of delayed allograft function was formulated based on the serum creatinine 2 weeks after transplantation. Unadjusted and adjusted logistic regression analysis were used to examine the unconfounded relationship between race and delayed allograft function.

RESULTS

Fifty-seven of 91 (62.6%) black recipients experienced delayed allograft function compared to 113 of 234 (48.3%) whites. The odds ratio for black race as a predictor of delayed allograft function was 1.80, P=0.02, (95% CI, 1.09, 2.95). This finding was stable despite adjustment for other predictors of delayed allograft function in a multivariate model, but the precision of this estimate was less (P=0.10) because of missing data. Additionally, adjusted models with imputed values for missing covariates, models using a secondary definition of delayed allograft function, and models excluding patients whose cyclosporin therapy was delayed, all consistently demonstrated a similar association between black race and delayed allograft function.

CONCLUSIONS

This study demonstrated an increased risk of delayed allograft function among black recipients. This relationship may play a role in the poorer allograft outcomes experienced by black recipients. Given the negative effect of delayed allograft function on allograft survival, efforts to identify its modifiable risk factors should be a high priority.

Lack of hepatotoxic effects of parenteral ketorolac in the hospital setting

BACKGROUND

No large controlled studies to date have examined the hepatic safety of parenteral ketorolac, which is used to treat acutely ill hospitalized patients who may be at greatest risk of liver injury.

OBJECTIVE

To measure the association between the use of parenteral ketorolac and subsequent liver injury.

METHODS

A nonexperimental cohort study conducted in 35 hospitals in the greater Philadelphia, Pa, region examined 10,272 courses of parenteral ketorolac (the exposed group) and 10,247 courses of parenteral opioid (the comparison group). Liver injury was defined by a modified international consensus definition that relied exclusively on liver function tests. Proportional hazards regression was used to calculate the rate ratio and 95% confidence interval for the association between ketorolac exposure and the occurrence of liver injury, controlling for potentially confounding factors, and to explore the possible effects of duration and dose.

RESULTS

The incidence of liver injury was 1.0% in the ketorolac group and 1.2% in the opioid group, yielding an unadjusted rate ratio of 0.77 (95% confidence interval, 0.59 1.01). Simultaneously adjusting for multiple potentially confounding factors did not change this result. There was no evidence for a duration-response relationship (P = .96) or a dose-response relationship (P = .23). We were unable to identify any subgroups that were susceptible to possible hepatotoxic effects of parenteral ketorolac.

CONCLUSIONS

This study failed to find evidence of a hepatotoxic effect of parenteral ketorolac use in the hospital setting and provides strong evidence against the existence of a clinically meaningful association between exposure to parenteral ketorolac in the hospital setting and liver injury.

Effect of anti-lymphocyte induction therapy on renal allograft survival: a meta-analysis

Induction immunosuppression with antilymphocyte antibodies has not been shown to improve cadaveric kidney allograft survival in randomized, controlled trials despite widespread use. This meta-analysis of randomized, controlled trials assessed the effectiveness of induction therapy in prolonging allograft survival. Studies of induction therapy were identified in Medline (1986 through 1996), using the terms "monoclonal antibodies" or "antilymphocyte serum," and "kidney transplantation," "human," and "clinical trial." Bibliographies, pharmaceutical manufacturers, the United Network for Organ Sharing, National Institutes of Health, and study authors were also consulted. Seven of 247 identified studies met the following inclusion criteria: (1) an adult study population; (2) assessment of antilymphocyte antibodies in the immediate posttransplant period; (3) a control arm of cyclosporine, azathioprine, and prednisone in the immediate posttransplant period; and (4) presentation of survival data. Two readers independently extracted protocol and survival data from each study. Summary odds ratios (fixed and random effects) and a rate ratio from proportional hazards regression at 2 yr were estimated to examine the effect of induction therapy on allograft survival. The summary odds ratios were both 0.66 (confidence interval [CI], 0.45 to 0.96; P = 0.03), and the rate ratio was 0.69 (CI, 0.49 to 0.97; P = 0.03), indicating a beneficial effect of induction therapy on allograft survival. Allograft survival was 85.6% (CI, 82.1 to 89.1%) in the induction therapy group and 79.6% (CI, 75.6 to 83.6%) in the conventional therapy group. These results were stable in a sensitivity analysis based on study quality. Allograft survival was prolonged with induction therapy compared with conventional immunosuppression. These data indicate a potential role for the routine use of induction therapy in renal transplantation to optimize the survival of cadaveric allografts.

National kidney allograft sharing: a decision analysis

BACKGROUND

Expansion of the current program of national sharing of cadaveric kidney allografts is of uncertain benefit, and the logistical barriers to expanding organ sharing are large. This study estimated the improvement in allograft survival from expanding organ sharing in the United States.

METHODS

A decision analysis based on allograft survival data from cadaveric allograft recipients throughout the United States compared the mean allograft survival resulting from four allograft-sharing strategies: no national sharing, national sharing of allografts matched at 6 histocompatibility alleles, national sharing of allografts matched at 4 or more alleles, and national sharing of allografts matched at 2 or more alleles.

RESULTS

Sharing allografts matched at 4 or more alleles was optimal (mean allograft survival=6.35 years). This survival was little better than the mean survival of the other three strategies (no national sharing, 6.21 years; national sharing of allografts matched at 6 alleles, 6.31 years; and sharing of allografts matched at 2 or more alleles, 6.33 years). The increment in the proportion of allografts surviving 4 years or more under the optimal strategy compared with no national sharing was <2%. A similar decision model comparing kidney transplant outcomes before and after the introduction of cyclosporine showed that this drug has had a much greater impact on mean allograft survival than would be expected to occur with national allograft sharing: 6.07 years with cyclosporine versus 3.79 years without cyclosporine.

CONCLUSIONS

Expanding national allograft sharing would achieve little improvement in mean allograft survival. The limited benefit and logistical barriers to expansion of allograft sharing should be considered before following recommendations to expand the current U.S. allograft-sharing program.

Epidemiological pitfalls using Medicaid data in reproductive health research

The purpose of this report is to discuss methodologic issues in using Medicaid claims data to conduct epidemiologic analyses in reproductive health. We conducted case-control studies that used Medicaid claims data to evaluate two specific reproductive health questions. Case and control pregnancies were selected from among 106,000 women identified in a Medicaid claims file. Medical record review was conducted for randomly selected cases and controls. Several methodological issues were identified. Women could contribute multiple pregnancies that qualified as either case pregnancies, control pregnancies, or both. The results of the medical record review indicated that 25% of one case group (low-birthweight infants) could not be confirmed, and 70% of the second case group (CNS birth defects) were misclassified. Thirty-five percent of women classified as not having undergone diagnostic ultrasonography based on Medicaid claims data had evidence of having received diagnostic ultrasound during pregnancy on the basis of medical record review. Several problems were encountered with the use of Medicaid billing data to address epidemiologic questions in reproductive health. Although solutions to some of these problems could be identified, others could not be addressed without careful review of the medical records. These limitations may not apply to all state Medicaid databases or other claims data, but they should be carefully considered when planning claims-based analyses of reproductive health issues.

Parenteral ketorolac: the risk for acute renal failure

BACKGROUND

Acute renal failure has been associated with parenteral ketorolac tromethamine, but the risk that is associated with this therapy has not been quantified.

OBJECTIVE

To compare the risk for acute renal failure associated with ketorolac with that associated with opioids.

DESIGN

Retrospective cohort study.

SETTING

35 hospitals in or near Philadelphia.

PATIENTS

Patients receiving 10,219 courses of parenteral ketorolac and patients receiving 10,145 courses of parenteral opioids.

MEASUREMENTS

Acute renal failure was defined by 1) an increase in the serum creatinine concentration of 50% or more and 2) either an absolute increase of 44.2 mumol/L or more for concentrations that were less than 132.6 mumol/L at baseline or an absolute increase of 88.4 mumol/L or more for concentrations that were 132.6 mumol/L or more at baseline. In addition, a secondary definition required a diagnosis by a physician.

RESULTS

The overall incidence of acute renal failure was 1.1% after therapy with either ketorolac or opioids. Multivariate-adjusted rate ratios comparing ketorolac with opioids for acute renal failure were 1.09 (95% CI, 0.83 to 1.42) overall, 1.00 (CI, 0.76 to 1.33) for less than 5 days of therapy, and 2.08 (CI, 1.08 to 4.00; P = 0.03) for more than 5 days of therapy. Similar results were obtained when the secondary definition of acute renal failure was used.

CONCLUSIONS

Overall, acute renal failure was uncommon in this hospitalized population. Compared with opioids, ketorolac administered for 5 days or less did not increase the rate of renal failure. However, among patients who were treated with analgesics for more than 5 days, ketorolac may be associated with an elevated rate of acute renal failure.

Effect of dialyzer reuse on survival of patients treated with hemodialysis

OBJECTIVE

To evaluate the impact of dialyzer reuse on the survival of US hemodialysis patients.

STUDY DESIGN AND PARTICIPANTS

Nonconcurrent cohort study of 27938 patients beginning hemodialysis in the United States in 1986 and 1987.

MAIN OUTCOME MEASURE

Patient survival.

RESULTS

Dialysis in freestanding facilities reprocessing dialyzers with the combination of peracetic and acetic acids was associated with greater mortality than treatment in facilities not reprocessing dialyzers (rate ratio [RR],1.10, 95% confidence interval [CI], 1.02-1.18; P=.02) In contrast, there was no significant difference between survival in freestanding facilities reprocessing dialyzers with either formaldehyde (RR,1.03, 95% CI, 0.96-1.10; P=.45) or glutaraldehyde (RR, 1.13, 95% CI, 0.95-1.35, P=.18) and survival in freestanding facilities not reprocessing dialyzers. Among freestanding facilities reprocessing dialyzers, use of peracetic/acetic acid was associated with a higher rate of death than use of formaldehyde (RR = 1.08, 95% CI, 1.01-1.14; P=.02). There was no statistical difference between survival in hospital-based facilities reprocessing dialyzers with either peracetic/acetic acid (RR=0.95, 95% CI, 0.85-1.06; P=.40), formaldehyde (RR=1.06, 95% CI, 0.98-1.15; P=.12), or glutaraldehyde (RR=1.09, 95% CI, 0.71-1.67; P=.70) and survival in hospital-based facilities not reprocessing dialyzers. In addition, choice of sterilant was not associated with a statistically significant difference in survival among hospital-based facilities reprocessing dialyzers.

CONCLUSIONS

Dialysis in freestanding facilities reprocessing dialyzers with peracetic/acetic acid may be associated with worse survival than dialysis in free-standing facilities not reprocessing dialyzers or in those reprocessing with formaldehyde. We were unable to determine whether these relationships arose from greater comorbidity among patients treated in facilities using peracetic/acetic acid, poor quality of dialysis procedures in these facilities, or direct toxicity of peracetic/acetic acid. These findings raise important concerns about potentially avoidable mortality among US hemodialysis patients treated in dialysis facilities reprocessing hemodialyzers.

Risk of foot complications in long-term diabetic patients with and without ESRD: a preliminary study

OBJECTIVE

The purpose of this preliminary study was to generate hypotheses for future research about the relationship between ESRD and foot complications in patients with long-term diabetes.

DESIGN

A cross-sectional prevalence study was conducted comparing a sample of long-term diabetic patients with ESRD to a sample of long-term diabetic patients without ESRD.

SAMPLE/SETTING

A convenience sample of 132 patients with long-term diabetes (> 15 years), with (N = 60) and without (N = 72) ESRD, was selected from ambulatory care settings and dialysis units.

METHODS

Data were collected by chart audit, structured interview, and physical examination.

RESULTS

Foot complications were greater in individuals with diabetes and ESRD (25%) than in diabetic individuals without ESRD (10%) (p = 0.02). Neither neuropathy, past or current smoking, race, gender, nor age were significantly associated with current foot complications (either current infection, ulcer, gangrene, or amputation).

CONCLUSIONS

Research is needed to better understand foot complications in persons with long-term diabetes and ESRD so that the effectiveness of nursing and medical interventions to stabilize or prevent foot complications can be evaluated.

Delayed function reduces renal allograft survival independent of acute rejection

BACKGROUND

Mechanisms by which delayed allograft function reduces renal allograft survival are poorly understood. This study evaluated the relationship of delayed allograft function to acute rejection and long-term survival of cadaveric allografts.

METHODS

338 recipients of cadaveric allografts were followed until death, resumption of dialysis, retransplantation, loss to follow-up, or the study's end, which ever came first. Delayed allograft function was defined by dialysis during the first week following transplantation. Multivariate Cox proportional hazards survival analysis was used to assess the relationship of delayed allograft function to rejection and allograft survival.

RESULTS

Delayed allograft function, recipient age, preformed reactive antibody levels, prior kidney transplantation, recipient race, rejection during the first 30 days and rejection subsequent to 30 days following transplantation were predictive of allograft survival in multivariate survival models. Delayed allograft function was associated with shorter allograft survival after adjustment for acute rejection and other covariates (relative rate of failure [RR]+1.72 [95% CI, 1.07, 2.76]). The adjusted RR of allograft failure associated with any rejection during the first 30 days was 1.99 (1.23, 3.21), and for rejection subsequent to the first 30 days was 3.53 (2.9 08, 6.00). The impact of delayed allograft function did not change substantially (RR=1.84 [1.15, 2.95]) in models not controlling for acute rejection. These results were stable among several subgroups of patients and using alternative definitions of allograft survival and delayed allograft function.

CONCLUSIONS

This study demonstrates that delayed allograft function and acute allograft rejection have important independent and deleterious effects on cadaveric allograft survival. These results suggest that the effect of delayed allograft function is mediated, in part, through mechanisms not involving acute clinical rejection.

Hemodialysis vascular access morbidity

Complications associated with hemodialysis vascular access represent one of the most important sources of morbidity among ESRD patients in the United States today. In this study, new data on the magnitude and growth of vascular access-related hospitalization in the United States is presented, demonstrating that the costs of this morbidity will soon exceed $1 billion per yr. This study also reviews published literature on the morbidity associated specifically with native arteriovenous fistulae, polytetrafluoroethylene bridge grafts, and permanent central venous catheters. Next, new information on the changing patterns of vascular access type in the United States is presented, demonstrating the continuing evolution of medical practice away from the use of arteriovenous fistulae in favor of more reliance on synthetic bridge grafts. Based on these data, a discussion is provided of the tradeoffs among the most commonly available modalities of vascular access today. Although radial arteriovenous fistulae continue to represent the optimal access modality, the appropriate roles for brachial arteriovenous fistulae, synthetic bridge grafts, and central venous catheters are less certain because of inadequate data on the long-term function of the first and the high rates of complications associated with the latter two. To reduce vascular access-related morbidity, strategies must be developed not only to prevent and detect appropriately early synthetic vascular access dysfunction, but to better identify the patients in a whom radial arteriovenous fistula is a viable clinical option.

Recipient body size and cadaveric renal allograft survival

Transplantation of renal allografts inadequate to meet recipient metabolic demands has been hypothesized to be one cause of chronic allograft failure. This cohort study examined the relationship of each of three measures of recipient body size and one measure of recipient metabolic rate to the rate of allograft failure among 239 recipients of cadaveric renal allografts between 1985 and 1990. All subjects were followed until allograft failure, death, or December 31, 1992, whichever occurred first. Using multivariate Cox proportional hazards analysis, all measures of recipient size and metabolic rate were found to be strong and statistically significant predictors of allograft survival adjusted for other predictors of allograft survival including allograft rejection, delayed allograft function, recipient race, prior renal transplantation, and donor age. The adjusted relative risk (RR) of allograft failure for a 15-kg increase in recipient body weight was 1.47, P < 0.0001 (95% confidence interval (CI), 1.21-1.78); adjusted RR for a 10-U increase in recipient body mass index was 2.34, P < 0.0001 (95% CI, 1.53-3.58); adjusted RR for a 0.5 m2 increase in recipient body surface area was 2.34, P < 0.001 (95% CI, 1.40-3.91); and adjusted RR for a 250 Kcal increase in metabolic rate was 1.49, P < 0.01 (95% CI, 1.17-1.89). These results are consistent with prior research indicating that a renal tissue supply-demand mismatch may accelerate failure of renal allografts. Alternative explanations of this relationship between recipient body size and allograft survival include inadequate immunosuppressive medication administration among recipients with a larger body size. Additional research is warranted to examine more fully the relationship between recipient body size and allograft survival.

Renal failure among male Hispanics in the United States

This study examined epidemiologic patterns and time trends among male patients with Hispanic surnames in the Medicare End-Stage Renal Disease Program and compared US Hispanics with non-Hispanic Blacks and Whites. Male Hispanics had substantially higher proportions of end-stage renal disease attributed to diabetes than did Blacks and Whites. There were notable regional differences among Hispanics. Between 1980 and 1990, the incidence of treated renal failure among Hispanics increased more than that among Blacks or Whites. The increasing number of Hispanics in the United States with end-stage renal disease emphasizes the importance of explicit health evaluations and prevention strategies for Hispanic populations.

Hemodialysis vascular access morbidity in the United States

Extensive morbidity related to hemodialysis vascular access exists among end-stage renal disease (ESRD) patients, but the risk factors for this morbidity have not been extensively studied. Medicare ESRD patient data were obtained from 1984, 1985, and 1986. Hospitalization for vascular access morbidity (ICD-996.1, 996.6, or 996.7) was analyzed among prevalent patients and, using survival analysis, among incident patients to assess sex, age, race, and underlying cause of renal failure as risk factors. We found that 15 to 16% of hospital stays among prevalent ESRD patients were associated with vascular access-related morbidity. Black race, older age, female sex, and diabetes mellitus as a cause of kidney failure were all independent risk factors for access-related morbidity. The rate ratio comparing Blacks to Whites was 1.12 (95% C.I., 1.09, 1.16); > 64 years to 20 to 44 years, 1.53 (1.46, 1.59); men to women, 0.81 (0.79, 0.84); and diabetes to glomerulonephritis, 1.29 (1.24, 1.35). We conclude that hemodialysis vascular access malfunction causes much hospitalization among ESRD patients. Women, Blacks, the elderly, and diabetics appear to be at particularly high risk, and additional studies are needed to understand these patterns.

Projections of hypertension-related renal disease in middle-aged residents of the United States

OBJECTIVE

To establish nationwide projections for hypertension-related renal disease among middle-aged residents of the United States and compare disease burden in demographic subgroups.

DESIGN

Integrated analysis of data from the US Census, the National Health and Nutrition Examination Survey of 1976 through 1980 (NHANES II), the 1971 through 1975 NHANES I Epidemiologic Follow-up Study, the Hypertension Detection and Follow-up Program trial, and the US Renal Data System.

POPULATION

African-American and white residents of the United States, aged 30 to 69 years.

MAIN OUTCOME MEASURES

Incidence rates and counts of hypertension, hypertension-related hypercreatinemia, and hypertension-related end-stage renal disease (ESRD).

RESULTS

Each year, approximately 1.8 million middle-aged Americans develop hypertension, 140,000 develop hypertension-related hypercreatinemia, and 5300 develop hypertension-related ESRD. African Americans are at increased risk for hypertension (relative risk [RR], 1.6; population-attributable risk [PAR], 5%), hypercreatinemia if hypertensive (RR, 2.4; PAR, 18%), ESRD if hypertensive with hypercreatinemia (RR, 2.7; PAR, 32%), and hypertension-related ESRD overall (RR, 8.0; PAR, 44%). Compared with women, men are at increased risk for hypertension (RR, 1.3; PAR, 13%) and hypertension-related ESRD (RR, 1.6; PAR, 23%). Most cases of hypercreatinemia in hypertensives (73%) occur among those with mild hypertension.

CONCLUSIONS

Progression to ESRD is rare in persons with hypertension-related renal disease, and factors other than blood pressure probably play an important role. A large proportion of hypertension-related renal disease cases occur among population subgroups considered to be at low risk. Interventions that favorably influence factors associated with the progression of hypertension-related renal disease in African Americans, in men, and in persons with mild hypertension, hold the greatest potential for reducing the population burden of hypertension-related ESRD.

End-stage renal disease in US minority groups

Medicare's End-Stage Renal Disease (ESRD) Program makes renal replacement services accessible for the majority of Americans with renal failure. National data from Medicare demonstrate complex and variable patterns of use of renal replacement services among US racial and ethnic groups. The black population has consistently suffered from a greater than 3.5-fold higher rate of treated ESRD than has the white population. The rates of hypertensive, diabetic, and glomerulopathic ESRD are all substantially greater in blacks than in whites, and hypertension has accounted for a far greater proportion of ESRD in blacks than any other diagnosis. There is a paucity of national data on the occurrence of ESRD in Hispanic Americans. However, data from Texas strongly suggest that the incidence rate of treated ESRD is much higher in Mexican Americans than in non-Hispanic whites. Higher rates are apparent for each of the three most important causes of ESRD: hypertension, diabetes, and glomerulonephritis. Native Americans experience ESRD at a rate intermediate between those of whites and blacks, but their rate of diabetic ESRD is higher than in either blacks or whites. However, considerable diversity exists among Native American tribal groups. Significant barriers to the acquisition of preventive care have been identified, especially for blacks. While these barriers to preventive care are accompanied by a significantly impaired health status of the black American population, a specific causal relationship between impaired access to care for blacks and their predisposition to ESRD has not been established.

A cohort study of transcutaneous oxygen tension and the incidence and severity of retinopathy of prematurity

BACKGROUND

Retinopathy of prematurity is a disease affecting the blood vessels of the retina in premature infants that may result in scarring, retinal detachment, and loss of vision. An association between this condition and the exposure of premature infants to supplemental oxygen has been postulated, but the relation between retinopathy of prematurity and blood oxygen levels has not been defined. The purpose of this study of a cohort of preterm infants was to correlate the incidence and severity of retinopathy of prematurity with the duration of exposure to different ranges of oxygen tension as measured by transcutaneous monitoring (tcPO2).

METHODS

One hundred one premature infants (birth weight, 500 to 1300 g) requiring supplemental oxygen had continuous monitoring of tcPO2. The number of hours during which the tcPO2 was 80 mm Hg or higher was tabulated for each infant during the first four weeks of life.

RESULTS

There was a significant association between the amount of time that the tcPO2 was greater than or equal to 80 mm Hg and the incidence and severity of retinopathy of prematurity. The odds ratio for each 12-hour period in which the tcPO2 was greater than or equal to 80 mm Hg was 1.9 (95 percent confidence interval, 1.2 to 3.0) after adjustment for the following factors: birth weight less than or equal to 1300 g (odds ratio, 2.3 [95 percent confidence interval, 1.6 to 3.4]), five-minute Apgar score of 7 or less (odds ratio, 7.2 [95 percent confidence interval, 2.5 to 21]), and exposure to inspired oxygen at a concentration greater than or equal to 0.4 (odds ratio, 1.0 [95 percent confidence interval, 0.97 to 1.05]). The association was stronger for tcPO2 values of greater than or equal to 80 mm Hg occurring from the second through the fourth week of life; during this period, the adjusted odds ratio for a 12-hour period of such exposure was 3.1 (95 percent confidence interval, 1.6 to 6.1).

CONCLUSIONS

This study supports an association between the incidence and severity of retinopathy of prematurity and the duration of exposure to arterial oxygen levels of 80 mm Hg or higher, measured transcutaneously.

Utilisation of drugs for diabetes mellitus

This article reviews the data from drug utilisation research on antidiabetic agents, oral hypoglycaemics and insulin. Study methods specific to this type of pharmacoepidemiological research are discussed and critiqued. A brief overview of the sources of drug utilisation data is presented, followed by a review of specific pharmacoepidemiological investigations. We evaluate the usefulness of these studies in assessing true drug consumption, in evaluating comorbidity in diabetic patients and in measuring the prevalence of diabetes. International comparisons of antidiabetic drug utilisation, also reviewed and analysed, demonstrate wide variations in the use of hypoglycaemic agents, which have arisen for reasons which are unclear. Drug utilisation research thus far has been limited by the paucity of studies relating these variations in antidiabetic drug use to specific clinical outcomes. There is a need to expand the applications of research on the use of antidiabetic agents, including assessment of patterns of morbidity across geographic boundaries and over time.

Changes in causes of death after renal transplantation, 1966 to 1987

This descriptive study was undertaken to examine survival and changes in cause of death after renal transplantation. One fourth (259) of the 1,022 patients who received a renal transplant between 1966 and 1987 at the University of Pennsylvania had died by January 1, 1988. Causes of death for 246 (96%) of the deceased patients were analyzed. Despite an increase in age and number of comorbid diseases before transplantation, posttransplant survival increased significantly over the study period. All-cause mortality rates at 1, 2, and 5 years decreased significantly. Infectious disease cumulative mortality rates at 1, 2, and 5 years also decreased between 1966 and 1985. No trend in the 1-, 2-, or 5-year cardiovascular disease cumulative mortality rates was detected. The decline in the rate of deaths due to infection led to a decrease in the proportion of infection-related deaths and an associated increase in the proportion of cardiovascular disease-related deaths. The reduction in mortality over the past 2 decades is associated with the simultaneous improvement in immunosuppression and treatment of infectious diseases.