Incidence of Long COVID-19 at 12-18 Months Following Delta Wave of Coronavirus Disease 2019: Hospital-based Prospective Registry.

Background and objective: Long coronavirus disease 2019 (COVID-19) has emerged as an important consequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To identify its incidence 12-18 months following hospitalization in patients with COVID-19, we performed a prospective study.

Methods: Virologically confirmed successive patients with moderate-to-severe COVID-19, hospitalized during the delta wave in India, were recruited. Data on clinical features, investigations, and outcomes were obtained. Long COVID-19 was diagnosed using the European quality of life questionnaire (EQ-5D) and Birmingham symptom burden questionnaire (SBQ) at 12-18-month follow-up.

Results: During the study period (January-July 2021), we evaluated 8,680 suspected COVID-19 patients, of whom 1,641 were confirmed virologically and 388 were hospitalized. Men accounted for 64.4%, individuals aged >60 years for 41.5%, hypertension for 42.8%, diabetes for 38.4%, and cardiovascular disease for 17.3%. At admission, there was a high prevalence of cough (71.1%), fever (86.6%), and oxygen requirement (38.6%). Proning was deployed in 89.2% of cases, nasal cannula in 36.3%, nonrebreather masks in 15.7%, noninvasive ventilation in 14.4%, and invasive ventilation in 16.2%. In-hospital deaths totaled 75 (19.3%), with 310 discharged for home care and eligible for follow-up. At a median follow-up of 15 months, 9 patients had died, 40 were lost to follow-up, and 264 were evaluated. The incidence of Long COVID-19 was 45 [17.0%, 95% confidence of interval (CI) 12.6-21.9%]. The median EQ-5D score was 5.0, with >5 observed in only 11 patients (0.6%). Using the SBQ, new-onset dyspnea on exertion was noted in 13 (4.9%), rest dyspnea in 7 (2.6%), fatigue in 31 (11.7%), feverishness in 18 (6.8%), and low energy in 16 (6.1%). Long COVID-19 was significantly more prevalent in women and older individuals. In Long COVID-19 compared to controls, the mean duration of oxygen requirement (5.46 ± 9.8 vs 2.46 ± 4.5 days, p = 0.002), use of nonrebreather masks (17.8 vs 7.3%, p = 0.026), noninvasive ventilation (11.1 vs 3.2%, p = 0.020), and duration of intensive care unit (ICU) stay (13.5, 8.7-17.3 vs 8.0, 5.0-11.0 days, p = 0.028) were significantly higher.

Conclusion: The incidence of Long COVID-19 at 12-18 months follow-up is 17.0%. It is significantly higher in women, older age groups, and patients requiring longer oxygenation, nonrebreather oxygen masks, noninvasive respiratory support, and extended stays in the ICU.