Long-Term Persistence and Recovery of Short-Term Memory Loss in COVID-19 Survivors: A 3.5-Year Follow-Up Study

Background

Short-term memory loss is a common persistent symptom reported in recovered COVID-19 patients. This study evaluated its long-term persistence in a cohort of hospitalized COVID-19 patients following discharge.

Materials and Methods

A total of 207 hospitalized COVID-19 patients were followed up for three and a half years after discharge. They were interviewed via telephone and asked about symptoms indicative of short-term memory loss, such as increased forgetfulness or difficulty retaining recent information. A memory loss score was then created based on their responses. A time-based recovery trend was plotted, which served as the basis for modeling the further course of the illness.

Additionally, a retrospective analysis of hospital records, including clinical, laboratory, and treatment data for each patient, was conducted. The test data were statistically compared with an age, sex, and comorbidity-matched cohort that did not exhibit significant long COVID symptoms.

Results

Short-term memory loss was observed in approximately 11.5% (24/207) of patients. After three and a half years, 25% (6/24) had fully recovered (faster recovery group), 37.5% (9/24) showed improvement (gradual recovery group), and 29% (7/24) exhibited little to no progress (slow recovery group). Two patients with memory loss passed away during the study. Time trend analysis revealed significant symptom recovery over the study period (p < 0.001). Model predictions based on trend data estimate the maximum recovery period for the gradual recovery group to be 3.7 years. However, symptoms in the slow recovery group may persist for up to 14 years. Higher age and comorbidities were the strongest predictors of recovery speed. In contrast, patient sex, blood group, hospital stay duration, illness severity, and levels of inflammatory, metabolic, and thrombosis markers during hospitalization showed no significant impact (p > 0.05) compared to the COVID-19 survivors with no memory loss or other long COVID symptoms.

Conclusion

Significant recovery from memory loss can occur over time in COVID-19 survivors; however, symptoms persist in most patients even three and a half years after hospital discharge. A longer follow-up period may be necessary to assess the long-term trajectory of long COVID patients.