Seronegative AAG more common in older patients

Older patients of autoimmune atrophic gastritis (AAG) tend to be seronegative for its hallmark biomarker, antiparietal cell antibodies (anti-PCA), a recent study has found.

The researchers conducted a cross-sectional analysis of 516 adult patients (mean age, 59.6±12.8 years) with histologically proven AAG. Indirect immunofluorescence and enzyme-linked immunosorbent assays were used for the detection of PCA.

Overall, 109 patients were seronegative (21.1 percent). This population tended to be older (p<0.0001) than their seropositive counterparts. The percentages of patients between 70–79 and ≥80 years of age were greater in the seronegative group; conversely, younger age groups were larger in the seropositive group.

Logistic regression analysis showed that the likelihood of seronegativity doubled among patients above the age of 50 years (odds ratio [OR], 2.4, 95 percent confidence interval, 1.13–5.25).

“The different time points of AAG natural history, in addition to the likely different duration of gastric disease of each included patient, could explain the higher occurrence of seronegativity in patients older than 70 years of age,” the researchers said.

Aside from age, endocrinological clinical features contributing to an AAG diagnosis was significantly more common among seropositive patients (p=0.04), as was the co-presence of other autoimmune diseases (p=0.04). Having a first-degree familial history of AAG was also more prevalent in seropositive patients, though only of borderline significance (p=0.08). None of these factors, however, achieved significance in logistic regression.