Abstract Body (Do not enter title and authors here): Background. Peripartum cardiomyopathy (PPCM) is defined as a dilated form of cardiomyopathy that occurs within the last month of pregnancy and up to 5 months postpartum. Previous studies have shown that PPCM more often occurs in the Southern United States compared to other geographic locations. Although the etiology of PPCM is likely multifactorial, viral infections may account for up to a third of those cases. We aimed to examine the association of PPCM to active influenza infection in the Southern United States.
Methods. National Inpatient Sample 2016-2021 was queried to identify women admitted with PPCM with (group A) and without (group B) concurrent influenza infection in the Southern United States.
Results. A total of 13540 women were admitted with PPCM, of whom 3511 (35%) had concurrent influenza infection. Group A PPCM followed a seasonal pattern with peak incidence in winter (62%) followed by spring (25%), fall (13%) and summer (0) [p<0.001]. Group A was older (mean age 33.6 -vs- 31.9), more often obese (16.8% -vs- 11.2%, p=0.011), had a smoking history (38.2% -vs- 26.1%, p<0.001), had higher Charlson comorbidity severity indexes (25.3% -vs- 17.2%, p=0.020), and had longer length of stay (6.1 -vs- 5.5). Group A also had higher rates of preexisting hypertension (15.3% -vs- 13.1%, p=0.011) and depression (18.8% -vs- 8.6%, p<0.001, OR 0.125 p-0.285), but similar rates of preeclampsia. In hospital mortality was not statistically significantly different between the two groups (1.8 -vs- 1.6%, p=0.067).
Conclusion. PPCM appears to follow a seasonal trend in incidence similar to influenza in the Southern United States. Influenza infection may account for some cases of PPCM in that region and may be associated with adverse in-hospital outcomes.