CO-FLOW: COvid-19 Follow-up care paths and Long-term Outcomes Within the Dutch health care system: study protocol of a multicenter prospective cohort study following patients 2 years after hospital discharge
Authors: Bek L. Martine , Berentschot Julia C. , Hellemons Merel E. , Huijts Susanne M. , Aerts Joachim G. J. V. , van Bommel Jasper , van Genderen Michel E. , Gommers Diederik A. M. P. J. , Ribbers Gerard M. , Heijenbrok-Kal Majanka H. , van den Berg-Emons Rita J. G. ,   the CO-FLOW Collaboration Group, Bek L. Martine , Berentschot Julia C. , Hellemons Merel E. , Huijts Susanne M. , Aerts Joachim G. J. V. , Heijenbrok-Kal Majanka H. , van den Berg-Emons Rita J. G. , Ribbers Gerard M. , van Bommel Jasper , van Genderen Michel E. , Gommers Diederik A. M. P. J. , Ista Erwin , van der Stoep Robert , Osterthun Rutger , Wijffels Markus P. J. M. , Slaman Jorrit , Visser Marieke M. , Tazmi-Staal Janette J. , Willems Eva G. , Heller Roxane , Gajadin Shai A. , Blox Wouter J. B. , Oswald Laurien , Bindraban Sieshem , Slingerland Rob , van de Sande Herbert J. , Kadir Hawre , van Lanen Marc , van Rossem Ronald N. , van Loon-Kooij Stephanie 
Published: August 2021

Abstract
Background
First studies indicate that up to 6 months after hospital discharge, coronavirus disease 2019 (COVID-19) causes severe physical, cognitive, and psychological impairments, which may affect participation and health-related quality of life (HRQoL). After hospitalization for COVID-19, a number of patients are referred to medical rehabilitation centers or skilled nursing facilities for further treatment, while others go home with or without aftercare. The aftercare paths include 1] community-based rehabilitation; 2] in- and outpatient medical rehabilitation; 3] inpatient rehabilitation in skilled nursing facilities; and 4] sheltered care (inpatient). These aftercare paths and the trajectories of recovery after COVID-19 urgently need long-term in-depth evaluation to optimize and personalize treatment. CO-FLOW aims, by following the outcomes and aftercare paths of all COVID-19 patients after hospital discharge, to systematically study over a 2-year period: 1] trajectories of physical, cognitive, and psychological recovery; 2] patient flows, healthcare utilization, patient satisfaction with aftercare, and barriers/facilitators regarding aftercare as experienced by healthcare professionals; 3] effects of physical, cognitive, and psychological outcomes on participation and HRQoL; and 4] predictors for long-term recovery, health care utilization, and patient satisfaction with aftercare.

Methods
CO-FLOW is a multicenter prospective cohort study in the mid-west of the Netherlands with a 2-year follow-up period. Measurements comprise non-invasive clinical tests and patient reported outcome measures from a combined rehabilitation, pulmonary, and intensive care perspective. Measurements are performed at 3, 6, 12, and 24 months after hospital discharge and, if applicable, at rehabilitation discharge. CO-FLOW aims to include at least 500 patients who survived hospitalization for COVID-19, aged ≥18 years.

Discussion
CO-FLOW will provide in-depth knowledge on the long-term sequelae of COVID-19 and the quality of current aftercare paths for patients who survived hospitalization. This knowledge is a prerequisite to facilitate the right care in the right place for COVID-19 and comparable future infectious diseases.

Trial registration
The Netherlands Trial Register (NTR), https://www.trialregister.nl. Registered: 12-06-2020, CO-FLOW trialregister no. NL8710.