Tuesday, September 16, 2014

Guideline adherence and outcomes in heart failure

Here's an interesting study from the International Journal of Cardiology:

Data on ambulatory patients (2006–2010) with CHF and reduced ejection fraction (HF-REF) from the Austrian Heart Failure Registry (HIR Austria) were analysed. One-year clinical data and long-term follow-up data until all-cause death or data censoring were available for 1014 patients (age 65 [55–73], male 75%, NYHA class I 14%, NYHA II 56%, NYHA III/IV 30%). A guideline adherence indicator (GAI [0–100%]) was calculated for each patient at baseline and after 12 ± 3 months that considered indications and contraindications for ACE-I/ARB, beta blockers, and MRA. Patients were considered ΔGAI-positive if GAI improved to or remained at high levels (greater than of equal to 80%). ΔGAI50+ positivity was ascribed to patients achieving a dose of greater than or equal to 50% of suggested target dose.

Improvements in GAI and GAI50+ were associated with significant improvements in NYHA class and NT-proBNP (1728 [740–3636] to 970 [405–2348]) (p less than 0.001). Improvements in GAI50+, but not GAI, were independently predictive of lower mortality risk (HR 0.55 [95% CI 0.34–0.87; p = 0.01]) after adjustment for a large variety of baseline parameters and hospitalisation for heart failure during follow-up.

Improvement in guideline adherence with particular emphasis on dose escalation is associated with a decrease in long-term mortality in ambulatory HF-REF subjects surviving one year after registration.

This is one explanation of why heart failure performance measures are not valid. They do not address titration of medications to goal.

Sunday, September 14, 2014

Limitations of the urine eosinophil test

From a retrospective study on the test characteristics for the diagnosis of acute interstitial nephritis (AIN):

This study identified 566 patients with both a UE test and a native kidney biopsy performed within a week of each other. Of these patients, 322 were men and the mean age was 59 years. There were 467 patients with pyuria, defined as at least one white cell per high-power field. There were 91 patients with AIN (80% was drug induced). A variety of kidney diseases had UEs. Using a 1% UE cutoff, the comparison of all patients with AIN to those with all other diagnoses showed 30.8% sensitivity and 68.2% specificity, giving positive and negative likelihood ratios of 0.97 and 1.01, respectively. Given this study’s 16% prevalence of AIN, the positive and negative predictive values were 15.6% and 83.7%, respectively. At the 5% UE cutoff, sensitivity declined, but specificity improved. The presence of pyuria improved the sensitivity somewhat, with a decrease in specificity. UEs were no better at distinguishing AIN from acute tubular necrosis compared with other kidney diseases.
Conclusions UEs were found in a variety of kidney diseases besides AIN. At the commonly used 1% UE cutoff, the test does not shift pretest probability of AIN in any direction. Even at a 5% cutoff, UEs performed poorly in distinguishing AIN from acute tubular necrosis or other kidney diseases.

Via Renal Fellow Network.

Saturday, September 13, 2014

Non-surgical management of appendicitis?

From a recent study:

During this 4-year study, we enrolled 26 elderly patients who initially received antibiotic therapy. Of these, 3 were suspected to have complicated appendicitis. Antibiotic therapy consisted of second-generation cephalosporin and metronidazole that was administered for 4 days with a 24 h fasting period. We evaluated the rates of treatment failure and recurrence.

Mean age was 83.5 years and 57.7% (15/26) of patients had comorbidities. One patient (4.8%) failed to respond to antibiotic therapy and underwent subsequent appendectomy. During the median follow-up period of 17 months, 5 patients (20%) experienced recurrence; 3 underwent appendectomy and two received a new course of antibiotics.

Antibiotic therapy without surgery may be a safe and an effective treatment for appendicitis in selective patients aged greater than or equal to 80 years. This is a good treatment option in patients with high operative risk.

Via Hospital Medicine Virtual Journal Club.

Sunday, September 07, 2014

Predicting spontaneous reperfusion from the initial ECG

From a recent paper in AJC:

Inversion of the T waves (T−) in electrocardiographic leads with ST-segment elevation after the initiation of reperfusion therapy is considered a sign of reperfusion. However, the significance of T− on presentation before the initiation of reperfusion therapy is unclear. The aim of this study was to assess whether T− on presentation predicts patency of the infarct-related artery in patients with acute ST-segment elevation myocardial infarctions (STEMIs)...Patency of the infarct-related artery (Thrombolysis In Myocardial Infarction [TIMI] flow grades 2 and 3) was seen in 64.3% of the patients in the T− group compared with only 31.2% in the T+/− group and 19.0% in the T+ group (p less than 0.001). Among patients with anterior STEMI, patency of the infarct-related artery was seen in all 7 patients in the T− group, compared with 50% of the 4 patients in the T+/− group and 10.1% of the 79 patients in the T+ group (p less than 0.001). There were no significant differences in TIMI flow grade among the groups in patients with nonanterior STEMIs (p = 0.985). In conclusion, T− in the leads with maximal ST-segment elevation on the presenting electrocardiogram was associated with higher prevalence of patency of the infarct-related artery before intervention (64.3%), especially in patients with anterior STEMIs (100%).

I looked at the example ECGs provided in the full text of this paper. Distinguishing complete T wave inversion from biphasic T waves when marked ST elevation is present is tricky.

Saturday, September 06, 2014

Thiazide induced hyponatremia

This review refers to it as a silent epidemic, under reported in clinical trials yet well known in the real clinical world.

The paper is a bit dated, and at the time it was published the use of desmopressin to help deal with over rapid correction had not been established.

Though not covered in the review it is worth mention that mere correction of the hypokalemia (which nearly always accompanies thiazide induced hyponatremia) can result in an overly rapid rise in the serum sodium.