Hospital Transfer Times and 30-Day Readmission Rates for PCI Studied

November 28, 2011—In the Archives of Internal Medicine, Jeph Herrin, PhD, et al published findings from a review of national door-in to door-out (DIDO) times for patients with acute ST-segment elevation myocardial infarction (2011;171:1879–1886). Also in the Archives of Internal Medicine, a study of factors associated with 30-day readmission rates after percutaneous coronary intervention (PCI) was published by Farhan J. Khawaha, MD, et al online ahead of print. 

In the first study, the investigators noted that because delays in treatment time are commonplace for ST-segment elevation myocardial infarction patients who must be transferred to another hospital for PCI, the recommended DIDO time should not exceed 30 minutes. DIDO time is a new measure developed by the Centers for Medicare & Medicaid Services that indicates the time of arrival at the first hospital to the time of transfer to the PCI hospital.

The investigators found that among patients presenting to emergency departments who require transfer to another facility for PCI, the DIDO time rarely met the recommended 30 minutes.

In the study, the investigators reported the national median DIDO time and examined associations with patient characteristics (age, sex, race, contraindication to fibrinolytic therapy, and arrival time) and hospital characteristics (number of beds, geographic region, location [rural or urban], and number of cases reported), using a mixed-effects multivariable model.

As detailed in the Archives of Internal Medicine, the investigators found that of 13,776 patients from 1,034 hospitals, only 1,343 (9.7%) had a DIDO time within 30 minutes, and DIDO exceeded 90 minutes for 4,267 patients (31%). The mean estimated times to transfer based on multivariable analysis were 8.9 (5.6–12.2) minutes longer for women, 9.1 (2.7–16) minutes longer for African Americans, 6.9 (1.6–11.9) minutes longer for patients with contraindication to fibrinolytic therapy, shorter for all age categories (except >75 years) relative to the category of 18 to 35 years, 15.3 (7.3–23.5) minutes longer for rural hospitals, and 14.4 (6.6–21.3) minutes longer for hospitals with nine or fewer transfers versus hospitals with 15 or more transfers in 2009 (95% confidence interval, all P < .001), reported the investigators.

In the second study, the investigators concluded that approximately one in 10 patients undergoing PCI were readmitted within 30 days and that 30-day readmission after PCI was associated with a higher risk of 1-year mortality.

As noted by the investigators, 30-day readmission rates have become a publicly reported quality performance measure for congestive heart failure, acute myocardial infarction, and PCI. However, little is known regarding the factors associated with 30-day readmission after PCI.

To assess the demographic, clinical, and procedural factors associated with 30-day readmission rates after PCI, the investigators studied 15,498 PCI hospitalizations (elective or for acute coronary syndromes) from January 1998 through June 2008 at Saint Marys Hospital in Rochester, Minnesota. All of those patients were included in this analysis.

The investigators stated that multivariate logistic regression models were used to estimate the adjusted association between demographic, clinical, and procedural variables and 30-day readmission. The association between 30-day readmission and 1-year mortality was estimated using Cox proportional hazards models with readmission as a time-dependent covariate and by using landmark analysis. The main outcome measures were all-cause 30-day readmission to any hospital following PCI and 1-year mortality.

As detailed in the Archives of Internal Medicine, the investigators found that, overall, 9.4% of PCI patients (n = 1459) were readmitted, and 0.68% of PCIs (n = 106) resulted in death within 30 days after discharge. Multivariate analysis determined that the factors associated with an increased risk of 30-day readmission after PCI were: female sex, Medicare insurance, having less than a high school education, unstable angina, cerebrovascular accident or transient ischemic attack, moderate-to-severe renal disease, chronic obstructive pulmonary disease, peptic ulcer disease, metastatic cancer, and a length of stay of more than 3 days. Thirty-day readmission after PCI was associated with a higher risk of 1-year mortality (adjusted hazard ratio, 1.38; 95% confidence interval, 1.08–1.75; P = .009), reported the investigators.