AMI Hospitalizations Associated With Laboratory-Confirmed IPD

Laboratory-confirmed invasive pneumococcal disease (IPD) is associated with an increased incidence of hospitalizations with acute myocardial infarction (AMI), according to a study in Clinical Infectious Diseases.

Researchers used state-based laboratory and hospital-based surveillance data to conduct a self-controlled case series study to evaluate the short- and long-term associations between laboratory-confirmed IPD and AMI.

Data were obtained from the Tennessee Active Bacterial Core Surveillance (ABCS) System and Tennessee Hospital Discharge Data System. Eligible participants were aged 18 years or older on the date they had their first hospitalization for AMI between July 1, 2004, and December 31, 2018, and they had a laboratory-confirmed IPD-related hospitalization within 365 days before or after the admission date of the hospitalization for AMI.

Follow-up continued up to an initial AMI hospitalization and through December 31, 2019, death, residence in a county not included in the ABCS system network, or day 365 after initial AMI hospitalization, whichever occurred first.

The AMI assessment periods were the first through seventh day before IPD specimen collection (pre-IPD detection), days 0 through day 7 after IPD specimen collection (current IPD), 8 to 28 days after IPD-specimen collection (post-IPD), and a control period (all other follow-up).

The primary outcome was evidence of AMI with ST-elevation MI, non-ST-elevation MI, or unspecified MI.

The analysis included 324 patients who had a specimen collection within 1 year before or after the earliest admission date for AMI. Of the cohort, 4.3% had another AMI within a year after the earliest AMI.

Among 338 hospitalizations for AMI, 191 (56.5%) involved an admission during the pre-IPD detection (5.6%), current (48.8%), or post-IPD (2.1%) periods. Of the 165 AMIs in the current IPD period, 86.7% had a positive IPD specimen collection on the date of admission for the AMI hospitalization.

The AMI incidence rate was greater during the pre-IPD detection period and current IPD period (306 and 2547.2 AMI per 100 person-years, respectively) vs the pre-IPD control (22.9 per 100 person-years), post-IPD secondary risk (48.3 per 100 person-years), and post-IPD control (41.8 per 100 person-years) periods.

The AMI incidence was nearly 93 times greater in the current IPD period compared with the pre- and post-IPD control periods (95% CI, 72.2-119.7) in the self-controlled case series analysis that accounted for age, study year, and seasonality. A nonsignificant but increased incidence of AMI was observed 1 to 7 days before IPD detection and 8 to 28 days after IPD detection.

Sensitivity analyses yielded consistent results, including the analysis with only the pre-IPD control period as reference, in which the risk for AMI was significantly increased in the post-IPD control period (29 to 365 days after IPD specimen collection) vs the pre-IPD control period (incidence rate ratio, 2.95; 95% CI, 2.01-4.32).

The researchers noted that the use of laboratory-confirmed IPD from the ABCS active surveillance system limited the ability to characterize the risk for AMI in patients with noninvasive or less severe Streptococcus pneumoniae infections or other infections that may not have been detected. Also, ascertainment bias is possible from hospitalizations for AMI regarding comorbid conditions. In addition, the study authors were unable to evaluate stratified analyses according to IPD treatment type and pneumococcal vaccination status.

“Since IPD is vaccine-preventable, effective vaccination programs that prevent IPD may also reduce the risk of major acute cardiovascular events,” the investigators wrote.

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.