Archives of internal medicine最新文献

Background: Although the tendency to repeat examinations is a major determinant of the capacity to serve new patients and of the ability to contain health care costs, little research has described the patterns observed in actual practice.

Methods: We investigated patterns of repeat testing in a longitudinal study of a 5% random sample of Medicare beneficiaries, restricted to 743,478 fee-for-service patients who were alive for a 3-year period after their index test between January 1, 2004, and December 31, 2006. Using the 50 largest metropolitan statistical areas as the unit of analysis, we examined the relationship between the proportion of the population tested and the proportion of tests repeated among those tested.

Results: Among beneficiaries undergoing echocardiography, 55% had a second test within 3 years. Repeat testing following other examinations was also common: 44% of imaging stress tests were repeated within 3 years, as were 49% of pulmonary function tests, 46% of chest computed tomography, 41% of cystoscopies, and 35% of upper endoscopies. The proportion of the population tested and the proportion of tests repeated varied across metropolitan statistical areas. The proportion who underwent echocardiography was highest in Miami, Florida (48%, among whom 66% of examinations were repeated in 3 years), and was lowest in Portland, Oregon (18%, among whom 47% of examinations were repeated in 3 years). Across 50 metropolitan statistical areas, the proportion of the population tested was consistently positively correlated with the proportion of tests repeated for echocardiography (Spearman r = 0.87, P < .001), imaging stress test (r = 0.65, P < .001), pulmonary function test (r = 0.62, P < .001), chest computed tomography (r = 0.66, P < .001), cystoscopy (r = 0.21, P = .13), and upper endoscopy (r = 0.59, P < .001).

Conclusions: Repeat testing is common among Medicare beneficiaries. Patients residing in metropolitan statistical areas with high rates of population testing are more likely to be tested and are more likely to have their test repeated.

Background: Enoxaparin sodium has predictable pharmacokinetics that allow for simplified dosing without laboratory monitoring. Reliance on renal function for excretion may lead to accumulation of enoxaparin in patients with moderate renal impairment. However, there is no dose adjustment recommended for these patients. We conducted a review to compare bleeding events in patients with moderate renal impairment compared with those with normal renal function.

Methods: Patients received enoxaparin sodium, 1 mg/kg, every 12 hours or 1.5 mg/kg once daily between June 1 and November 30, 2009. Moderate renal impairment was defined as creatinine clearance (CrCl) of 30 to 50 mL/min. Normal renal function was defined as CrCl greater than 80 mL/min. The primary outcome was major bleeding, defined as any bleeding resulting in death, hospital admission, lengthened hospital stay, or an emergency department visit. The secondary outcome was thromboembolism.

Results: A total of 164 patients met the inclusion criteria: 105 with normal renal function and 59 with moderate renal impairment. The primary outcome occurred in 6 of 105 patients (5.7%) with normal renal function vs 13 of 59 patients (22.0%) with moderate renal impairment, representing an unadjusted odds ratio of 4.7 (95% CI, 1.7-13.0; P = .002). The odds ratio using multivariable logistic regression adjusting for differences in risk was 3.9 (95% CI, 0.97-15.6; P = .055). There was no recurrent thromboembolism in either group.

Conclusions: Our results suggest an increased risk of major bleeding in patients with moderate renal impairment who receive enoxaparin. Because enoxaparin is frequently used and outcomes can be life saving or life threatening, we encourage further study of the appropriate dose in patients with moderate renal impairment.