A randomized multicenter study of the outcome of brachial-basilic arteriovenous fistula and prosthetic brachial-antecubital forearm loop as vascular access for hemodialysis

BackgroundVascular access is a necessity for patients with end-stage renal disease who need chronic intermittent hemodialysis. According to Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines, radial-cephalic (RC) and brachial-cephalic (BC) arteriovenous fistulas (AVF) are the first and second choice for vascular access, respectively. If these options are not possible, an autogenous brachial-basilic fistula in the upper arm (BBAVF) or a prosthetic brachial-antecubital forearm loop (PTFE loop) may be considered. Until now, it was not clear which access type was preferable. We have performed a randomized study comparing BBAVF and prosthetic implantation in patients without the possibility for RCAVF or BCAVF.MethodsPatients with failed primary/secondary access or inadequate arterial and/or venous vessels were randomized for either BBAVF or PTFE loop creation. The numbers of complications and interventions were recorded. Kaplan-Meier method was used to calculate primary, assisted-primary and secondary patency rates. The patency rates were compared with the log-rank test. Complication and intervention rates were compared with the Mann-Whitney test.ResultsA total of 105 patients were randomized for a BBAVF or PTFE loop (52 vs 53, respectively). Primary and assisted-primary 1-year patency rates were significantly higher in the BBAVF group: 46% ± 7.4% vs 22% ± 6.1% (P = .005) and 87% ± 5.0% vs 71% ± 6.7% (P = .045) for the BBAVF and PTFE group, respectively. Secondary patencies were comparable for both groups; 89% ± 4.6% vs 85% ± 5.2% for the BBAVF and PTFE group, respectively. The incidence rate of complications was 1.6 per patient-year in the BBAVF group vs 2.7 per patient-year in the PTFE group. Patients in the BBAVF group needed a total of 1.7 interventions per patient-year vs 2.7 per patient-year for the PTFE group.ConclusionThese data show a significantly better primary and assisted-primary patency in the BBAVF group compared with the PTFE group. Furthermore, in the BBAVF group, fewer interventions were needed. Therefore, we conclude that BBAVF is the preferred choice for vascular access if RCAVF or BCAVF creation is impossible, or when these types of access have already failed

How to deal with cost differences at baseline

BACKGROUND: To our knowledge, adjustment for baseline imbalances in costs has never been performed in trial-based cost-effectiveness analyses. METHODS: We used data from a clinical trial performed in the Netherlands comparing two outpatient psychotherapies: schema-focused therapy (SFT) versus transference-focused psychotherapy (TFP). Costs were assessed with a cost interview. Outcome was the proportion of recovered patients measured with the Borderline Personality Disorder Severity Index (BPDSI-IV). We used three methods to adjust the costs for baseline differences: (i) mean difference adjustment, calculating total costs after baseline by adjusting the difference between groups with the difference of the mean baseline costs; (ii) delta adjustment, calculating the individual differences between patient baseline and the subsequent measurements (concerning incremental costs, this is the same as mean difference adjustment); and (iii) regression-based adjustment, adjusting total costs with a regression model, with total costs as the dependent variable and baseline costs as the independent variable. RESULTS: Mean baseline costs were 3339 euros for SFT and 4238 euros for TFP, a mean difference of 899 euros. Total unadjusted follow-up costs were 30822 euros for SFT and 36812 euros for TFP. The fraction of recovered patients was 45% for SFT and 24% for TFP. Cost-effectiveness acceptability curves show that mean difference and delta adjustments are different from the regression-based methods. CONCLUSIONS: Although the routine starting point of an analysis should always be an unadjusted analysis of the cost effectiveness, a baseline difference between treatment groups should be adjusted for. This should be done by reported patient characteristics or, when these are not sufficiently present, by baseline costs as a substitute. This adjustment should be carried out most preferably with a regression-based method

How to Deal with Cost Differences at Baseline

Background To our knowledge, adjustment for baseline imbalances in costs has never been performed in trial-based cost-effectiveness analyses. Abstract: Methods We used data from a clinical trial performed in the Netherlands comparing two outpatient psychotherapies: schema-focused therapy (SFT) versus transference-focused psychotherapy (TFP). Costs were assessed with a cost interview. Outcome was the proportion of recovered patients measured with the Borderline Personality Disorder Severity Index (BPDSI-IV). We used three methods to adjust the costs for baseline differences: (i) mean difference adjustment, calculating total costs after baseline by adjusting the difference between groups with the difference of the mean baseline costs; (ii) delta adjustment, calculating the individual differences between patient baseline and the subsequent measurements (concerning incremental costs, this is the same as mean difference adjustment); and (iii) regression-based adjustment, adjusting total costs with a regression model, with total costs as the dependent variable and baseline costs as the independent variable. Abstract: Results Mean baseline costs were €3339 for SFT and €4238 for TFP, a mean difference of €899. Total unadjusted follow-up costs were €30 822 for SFT and €36 812 for TFP. The fraction of recovered patients was 45% for SFT and 24% for TFP. Cost-effectiveness acceptability curves show that mean difference and delta adjustments are different from the regression-based methods. Abstract: Conclusions Although the routine starting point of an analysis should always be an unadjusted analysis of the cost effectiveness, a baseline difference between treatment groups should be adjusted for. This should be done by reported patient characteristics or, when these are not sufficiently present, by baseline costs as a substitute. This adjustment should be carried out most preferably with a regression-based method.

Therapietrouw bij de behandeling van hypertensie: Combinatie van meetmethoden geeft meer inzicht in innamegedrag

OBJECTIVE: To investigate adherence patterns in detail by comparing and matching electronically derived adherence data with pill count data and the effect of adherence on blood pressure reduction in patients with mild to moderate hypertension. DESIGN: Observational study. METHODS: Among a total of 228 patients with mild to moderate hypertension, adherence to treatment was measured by means of both the Medication Event Monitoring System (MEMS) and pill count. Patients were followed up for seven visits over a period of one year. At each visit to the physician's office, patient's adherence was assessed by both methods. RESULTS: Median adherence according to MEMS was lower than median adherence according to pill count (91.6% vs. 96.1%; P < 0.001). Both methods agreed in defining patients as adherent in 107 (47%) and nonadherent in 33 (14%) cases. 31 patients (14%) were considered adherent only by MEMS and 59 patients (25%) only by pill count. At the end of the study, patients in the four categories reached comparable blood pressure values, and reductions. CONCLUSION: Pill count can be a useful adjunct to electronic monitoring in assessing adherence patterns. Although deviant intake behaviour occurred frequently, the effect on achieved blood pressure and blood pressure reduction was not remarkable

Assessing medication adherence simultaneously by electronic monitoring and pill count in patients with mild to moderate hypertension

OBJECTIVE: To investigate adherence patterns in detail by comparing and matching electronically derived adherence data with pill count data and the effect of adherence on blood pressure reduction in patients with mild to moderate hypertension. DESIGN: Observational study. METHODS: Among a total of 228 patients with mild to moderate hypertension, adherence to treatment was measured by means of both the Medication Event Monitoring System (MEMS) and pill count. Patients were followed up for seven visits over a period of one year. At each visit to the physician's office, patient's adherence was assessed by both methods. RESULTS: Median adherence according to MEMS was lower than median adherence according to pill count (91.6% vs. 96.1%; P &lt; 0.001). Both methods agreed in defining patients as adherent in 107 (47%) and nonadherent in 33 (14%) cases. 31 patients (14%) were considered adherent only by MEMS and 59 patients (25%) only by pill count. At the end of the study, patients in the four categories reached comparable blood pressure values, and reductions. CONCLUSION: Pill count can be a useful adjunct to electronic monitoring in assessing adherence patterns. Although deviant intake behaviour occurred frequently, the effect on achieved blood pressure and blood pressure reduction was not remarkable.</p

Accuracy of computed tomographic angiography and magnetic resonance angiography for diagnosing renal artery stenosis

Background: Timely, accurate detection of renal artery stenosis is important because this disorder may be a potentially curable cause of hypertension and renal impairment. Objective: To determine the validity of computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) compared with digital subtraction angiography (DSA) for detection of renal artery stenosis. Design: Prospective multicenter comparative study conducted from 1998 to 2001. Two panels of 3 observers judged CTA and MRA image data and were blinded to all other results. Digital subtraction angiography images were evaluated by consensus. Setting: 3 large teaching hospitals and 3 university hospitals in the Netherlands. Patients: 402 hypertensive patients with suspected renal artery stenosis were included. A group of 356 patients who underwent all 3 diagnostic tests was used for analysis. Measurements: Reproducibility was assessed by calculating interobserver agreement. Diagnostic performance was evaluated in terms of sensitivity, specificity, and other diagnostic variables. Atherosclerotic stenoses of 50% or greater and fibromuscular dysplasia were considered clinically relevant. Results: Twenty percent of patients who underwent all 3 tests had clinically relevant renal artery stenosis. Moderate interobserver agreement was found, with κ values ranging from 0.59 to 0.64 for CTA and 0.40 to 0.51 for MRA. The combined sensitivity and specificity were 64% (95% CI, 55% to 73%) and 92% (CI, 90% to 95%) for CTA and 62% (CI, 54% to 71%) and 84% (CI, 81% to 87%) for MRA. Limitations: Eighteen percent of the patients were included nonconsecutively. Digital subtraction angiography may be an imperfect reference test. Conclusion: Computed tomographic angiography and MRA are not reproducible or sensitive enough to rule out renal artery stenosis in hypertensive patients. Therefore, DSA remains the diagnostic method of choice.</p

Accuracy of computed tomographic angiography and magnetic resonance angiography for diagnosing renal artery stenosis

Background: Timely, accurate detection of renal artery stenosis is important because this disorder may be a potentially curable cause of hypertension and renal impairment. Objective: To determine the validity of computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) compared with digital subtraction angiography (DSA) for detection of renal artery stenosis. Design: Prospective multicenter comparative study conducted from 1998 to 2001. Two panels of 3 observers judged CTA and MRA image data and were blinded to all other results. Digital subtraction angiography images were evaluated by consensus. Setting: 3 large teaching hospitals and 3 university hospitals in the Netherlands. Patients: 402 hypertensive patients with suspected renal artery stenosis were included. A group of 356 patients who underwent all 3 diagnostic tests was used for analysis. Measurements: Reproducibility was assessed by calculating interobserver agreement. Diagnostic performance was evaluated in terms of sensitivity, specificity, and other diagnostic variables. Atherosclerotic stenoses of 50% or greater and fibromuscular dysplasia were considered clinically relevant. Results: Twenty percent of patients who underwent all 3 tests had clinically relevant renal artery stenosis. Moderate interobserver agreement was found, with κ values ranging from 0.59 to 0.64 for CTA and 0.40 to 0.51 for MRA. The combined sensitivity and specificity were 64% (95% CI, 55% to 73%) and 92% (CI, 90% to 95%) for CTA and 62% (CI, 54% to 71%) and 84% (CI, 81% to 87%) for MRA. Limitations: Eighteen percent of the patients were included nonconsecutively. Digital subtraction angiography may be an imperfect reference test. Conclusion: Computed tomographic angiography and MRA are not reproducible or sensitive enough to rule out renal artery stenosis in hypertensive patients. Therefore, DSA remains the diagnostic method of choice.</p