Surgical Outcome Reporting. Moving From a Comic to a Tragic Opera?

OBJECTIVES: To assess the current quality of surgical outcome reporting in the medical literature and to provide recommendations for improvement. BACKGROUND: In 1996, The Lancet labeled surgery as a "comic opera" mostly referring to the poor quality of outcome reporting in the literature impeding improvement in surgical quality and patient care. METHODS: We screened 3 first-tier and 2 second-tier surgical journals, as well as 3 leading medical journals for original articles reporting on results of surgical procedures published over a recent 18-month period. The quality of outcome reporting was assessed using a prespecified 12-item checklist. RESULTS: Six hundred twenty-seven articles reporting surgical outcomes were analyzed, including 125 randomized controlled trials. Only 1 (0.2%) article met all 12 criteria of the checklist, whereas 356 articles (57%) fulfilled less than half of the criteria. The poorest reporting was on cumulative morbidity burden, which was missing in 94% of articles (n=591) as well as patient-reported outcomes missing in 83% of publications (n=518). Comparing journal groups for the individual criterion, we found moderate to very strong statistical evidence for better quality of reporting in high versus lower impact journals for 7 of 12 criteria and strong statistical evidence for better reporting of patient-reported outcomes in medical versus surgical journals ( P <0·001). CONCLUSIONS: The quality of outcomes reporting in the medical literature remains poor, lacking improvement over the past 20 years on most key end points. The implementation of standardized outcome reporting is urgently needed to minimize biased interpretation of data thereby enabling improved patient care and the elaboration of meaningful guidelines.

Milestones in Surgical Complication Reporting: Clavien-Dindo Classification 20 Years and Comprehensive Complication Index 10 Years.

OBJECTIVE: To provide improved guidance for the consistent application of the Clavien-Dindo classification (CDC) and Comprehensive Complication Index (CCI ® ) in challenging clinical scenarios. BACKGROUND: Standardized outcome reporting is key for the proper assessment of surgical procedures. A recent consensus conference recommended the CDC and the CCI ® for assessing postoperative morbidity. Several challenging scenarios for grading complications still require evidence-based guidance, and the use of the 2 metrics in randomized controlled trials (RCTs) remains unexplored. METHODS: We assessed the use of the CDC and CCI ® as an outcome measure in a systematic literature search. In addition, we asked 163 international surgeons to critically evaluate and independently grade complications in 20 complex clinical scenarios. Finally, a Core Group of 5 experts used this information to develop consistent recommendations. RESULTS: Until July 2023, 1327 RCTs selected the CDC and/or CCI ® to assess morbidity. Annual use was steadily increasing with now over 200 new RCTs per year. However, only a third (n = 335) of published RCTs provided the complete range of CDC grades, including all subgrades. Eighty-nine out of 163 surgeons (response rate: 55%) completed the questionnaire that served as a basis for the recommendations: repetitive interventions that are required to treat one complication, complications followed by further complications, complications occurring before referral, and expected and unrelated complications to the original procedure should all be counted separately and included in the CCI ® . Invasive blank diagnostic interventions should not be considered a complication. CONCLUSIONS: The increasing use of the CDC and CCI ® in RCTs highlights the importance of their standardized application. The current consensus on various difficult scenarios may offer novel guidance for the consistent use of the CDC and CCI ® , aiming to improve complication reporting and better quality control, ultimately benefiting all health care stakeholders and, first and foremost, all patients.

Experts vs. machine - comparison of machine learning to expert-informed prediction of outcome after major liver surgery.

BACKGROUND: Machine learning (ML) has been successfully implemented for classification tasks (e.g., cancer diagnosis). ML performance for more challenging predictions is largely unexplored. This study's objective was to compare machine learning vs. expert-informed predictions for surgical outcome in patients undergoing major liver surgery. METHODS: Single tertiary center data on preoperative parameters and postoperative complications for elective hepatic surgery patients were included (2008-2021). Expert-informed prediction models were established on 14 parameters identified by two expert liver surgeons to impact on postoperative outcome. ML models used all available preoperative patient variables (n = 62). Model performance was compared for predicting 3-month postoperative overall morbidity. Temporal validation and additional analysis in major liver resection patients were conducted. RESULTS: 889 patients included. Expert-informed models showed low average bias (2-5 CCI points) with high over/underprediction. ML models performed similarly: average prediction 5-10 points higher than observed CCI values with high variability (95% CI -30 to 50). No performance improvement for major liver surgery patients. CONCLUSION: No clinical relevance in the application of ML for predicting postoperative overall morbidity was found. Despite being a novel hype, ML has the potential for application in clinical practice. However, at this stage it does not replace established approaches of prediction modelling.

Implementation and validation of a novel instrument for the grading of unexpected events in paediatric surgery: Clavien-Madadi classification.

BACKGROUND: Inconsistent definitions of complications and unexpected events have limited accurate analysis of surgical outcomes. Perioperative outcome classifications currently used for adult patients have limitations when used for children. METHODS: A multidisciplinary group of experts modified the Clavien-Dindo classification to increase its utility and accuracy in paediatric surgery cohorts. Organizational and management errors were considered in the novel Clavien-Madadi classification, which focuses on procedural invasiveness rather than anaesthetic management. Unexpected events were prospectively documented in a paediatric surgery cohort. Results of the Clavien-Dindo and Clavien-Madadi classifications were compared and correlated with procedure complexity. RESULTS: Unexpected events were prospectively documented in a cohort of 17 502 children undergoing surgery between 2017 and 2021. The results of both classifications were highly correlated (ρ = 0.95), although the novel Clavien-Madadi classification identified 449 additional events (organizational and management errors) over the Clavien-Dindo classification, increasing the total number of events by 38 per cent (1605 versus 1158 events). The results of the novel system correlated significantly with the complexity of procedures in children (ρ = 0.756). Furthermore, grading of events > grade III according to the Clavien-Madadi classification showed a higher correlation with procedure complexity (ρ = 0.658) than the Clavien-Dindo classification (ρ = 0.198). CONCLUSION: The Clavien-Madadi classification is a tool for the detection of surgical and non-medical errors in paediatric surgery populations. Further validation in paediatric surgery populations is required before widespread use.

Interdisciplinary approach in emergency revascularization and treatment for acute mesenteric ischemia.

BACKGROUND: Mesenteric ischemia is associated with poor outcome and high overall mortality. The aim was to analyze an interdisciplinary treatment approach of vascular and visceral specialists focusing on the in-hospital outcome and follow-up in patients with acute and acute-on-chronic mesenteric ischemia. METHODS: From 2010 until 2017, 26 consecutive patients with acute or acute on chronic mesenteric ischemia were treated by an interdisciplinary team. Data were prospectively collected and retrospectively evaluated. Throughout the initial examination, the extent of bowel resection was determined by the visceral surgeon and the appropriate mode of revascularization by the vascular surgeon. The routine follow-up included clinical examination and ultrasound- or CT-imaging for patency assessment and overall survival as primary endpoint of the study. RESULTS: Out of 26 patients, 18 (69.2%) were rendered for open repair. Ten patients (38.5%) received reconstruction of the superior mesenteric artery with an iliac-mesenteric bypass. Seven patients (26.9%) underwent thrombembolectomy of the mesenteric artery. One patient received an infra-diaphragmatic aorto-celiac-mesenteric bypass. Out of the 8 patients, who were not suitable for open revascularization, 2 patients (7.7%) were treated endovascularly and 6 (23.1%) underwent explorative laparotomy. The in-hospital mortality was 23% (n = 6). The mean survival of the revascularized group (n = 20) was 51.8 months (95% CI 39.1-64.5) compared to 15.7 months in the non-revascularized group (n = 6) (95% CI - 4.8-36.1; p = 0.08). The median follow-up was 64.6 months. Primary patency in the 16 patients after open and 2 after interventional revascularization was 100% and 89.9% in the follow-up. CONCLUSION: The interdisciplinary treatment of mesenteric ischemia improves survival if carried out in time. Hereby open revascularization measures are advantageous as they allow bowel assessment, resection, and revascularization in a one-stop fashion especially in advanced cases.

Can Early Postoperative Complications Predict High Morbidity and Decrease Failure to Rescue Following Major Abdominal Surgery?

OBJECTIVE: To assess whether specific patterns of early postoperative complications may predict overall severe morbidity after major surgery, warranting early escalation of care and prevention of failure to rescue. SUMMARY OF BACKGROUND DATA: It is unclear whether early postoperative complications predict a poor outcome. Detailed knowledge of the chronology and type of early complications after major surgery may alert clinicians when to expect higher risk for subsequent major negative events. METHODS: All 90-day postoperative events following complex pancreas, liver, and rectal surgeries, and liver transplantation were analyzed over a 3-year period in a single tertiary center. Each complication was recorded regarding severity, type (cardiac, infectious, etc), etiology (surgical/medical), and timing of occurrence. The Comprehensive Complication Index (CCI), covering the first 7 postoperative days, was calculated as a measure for early cumulative postoperative morbidity. The statistical analysis (descriptive, sequence pattern analyses, and logistic regression analyses) aimed to detect any combinations of events predicting poor outcome as defined by a cumulative CCI ≥37.1 at 90-days. RESULTS: The occurrence of ≥2 complications, irrespective of severity, type or etiology, was strongly associated with a severe postoperative course (P < 0.001). Even 2 mild complications (≤ grade II) greatly increased the chance for high morbidity compared to patients with 0 or 1 complication within the first postoperative week (odds ratio 10.2, 95% confidence interval 5.82-17.98). The CCI at postoperative day 7 strongly predicted high 90-day morbidity (odds ratio 3.96 per 10 CCI points, P < 0.001). CONCLUSION: Multiple complications of any cause or severity within the first postoperative days represents a "warning-signal" for overall high morbidity by 90 days, which should be used to trigger an escalation of care to prevent failure to rescue and eventually poor outcome.

SARS-CoV-2 Quarantine Mandated by Contact Tracing: Burden and Infection Rate Among Close Contacts in Zurich, Switzerland, 2020-2021.

Objectives: Before vaccines and effective treatments were available, quarantine of close contacts was important to limit the spread of SARS-CoV-2. To evaluate potential benefits and harms of quarantine, we aimed to estimate infection rates and describe experiences and mental health among persons in mandated quarantine during the early SARS-CoV-2 pandemic. Methods: We invited adults in mandated quarantine after an exposure to SARS-CoV-2 identified through contact tracing of the Canton of Zurich, Switzerland, between August 2020 and January 2021. Participants completed two questionnaires and received up to two SARS-CoV-2 polymerase chain reaction tests, during and at the end of quarantine. Results: Among 395 participants, quarantine duration ranged from 2 to 20 days. By day 11 since the last contact, 11.1% [95% CI 8.4%-14.7%] were infected with SARS-CoV-2. The proportion of participants with symptoms of depression doubled from 9.3% before quarantine to 18.9% during quarantine, and 12.1% reported quarantine was very or extremely difficult. Conclusion: Although quarantine was only moderately burdensome for most participants, some experienced significant difficulties and burden. Policymakers need to balance infection control with potential harms placed on individuals.

Validation of the Clavien-Madadi Classification for Unexpected Events in Pediatric Surgery: A Collaborative ERNICA Project.

BACKGROUND: The Clavien-Madadi classification is a novel instrument for the assessment and grading of unexpected events in pediatric surgery, based on the Clavien-Dindo classification. The system has been adjusted to better fit the pediatric population in a prospective single-center study. There is a need now to validate the Clavien-Madadi classification within an international expert network. METHODS: A pediatric surgical working group created 19 case scenarios with unexpected events in a multi-staged process. Those were circulated within the European Reference Network of Inherited and Congenital Anomalies (ERNICA) and surgeons were instructed to rate the scenarios according to the Clavien-Madadi vs. Clavien-Dindo classification. RESULTS: 59 surgeons from 12 European countries completed the questionnaire. Based on ratings of the case scenarios, the Clavien-Madadi classification showed significantly superior agreement rates of the respondents (85.9% vs 76.2%; p < 0.05) and was less frequently considered inaccurate for rating the pediatric population compared to Clavien-Dindo (2.1% vs 11.1%; p = 0.05). Fleiss' kappa analysis showed slightly higher strength of agreement using the Clavien-Madadi classification (0.74 vs 0.69). Additionally, intraclass correlation coefficient was slightly higher for the Clavien-Madadi compared to the Clavien-Dindo classification (ICCjust 0.93 vs 0.89; ICCunjust 0.93 vs 0.89). More pediatric surgeons preferred the Clavien-Madadi classification for the case scenarios (43.0% vs 11.8%; p = 0.002) and advantages of the Clavien-Madadi were confirmed by 81.4% of the surgeons. CONCLUSION: The Clavien-Madadi classification is an accurate and reliable instrument for the grading of unexpected events in pediatric surgery. We therefore recommend its application in clinical and academic pediatric surgical practice. LEVEL OF EVIDENCE: III.

Consensus recommendations on how to assess the quality of surgical interventions.

Postoperative complications represent a major public health burden worldwide. Without standardized, clinically relevant and universally applied endpoints, the evaluation of surgical interventions remains ill-defined and inconsistent, opening the door for biased interpretations and hampering patient-centered health care delivery. We conducted a Jury-based consensus conference incorporating the perspectives of different stakeholders, who based their recommendations on the work of nine panels of experts. The recommendations cover the selection of postoperative outcomes from the perspective of patients and other stakeholders, comparison and interpretation of outcomes, consideration of cultural and demographic factors, and strategies to deal with unwarranted outcomes. With the recommendations developed exclusively by the Jury, we provide a framework for surgical outcome assessment and quality improvement after medical interventions, that integrates the main stakeholders' perspectives.

Recovery and symptom trajectories up to two years after SARS-CoV-2 infection: population based, longitudinal cohort study.

OBJECTIVE: To evaluate longer term symptoms and health outcomes associated with post-covid-19 condition within a cohort of individuals with a SARS-CoV-2 infection. DESIGN: Population based, longitudinal cohort. SETTING: General population of canton of Zurich, Switzerland. PARTICIPANTS: 1106 adults with a confirmed SARS-CoV-2 infection who were not vaccinated before infection and 628 adults who did not have an infection. MAIN OUTCOME MEASURES: Trajectories of self-reported health status and covid-19 related symptoms between months six, 12, 18, and 24 after infection and excess risk of symptoms at six months after infection compared with individuals who had no infection. RESULTS: 22.9% (95% confidence interval 20.4% to 25.6%) of individuals infected with SARS-CoV-2 did not fully recover by six months. The proportion of individuals who had an infection who reported not having recovered decreased to 18.5% (16.2% to 21.1%) at 12 months and 17.2% (14.0% to 20.8%) at 24 months after infection. When assessing changes in self-reported health status, most participants had continued recovery (68.4% (63.8% to 72.6%)) or had an overall improvement (13.5% (10.6% to 17.2%)) over time. Yet, 5.2% (3.5% to 7.7%) had a worsening in health status and 4.4% (2.9% to 6.7%) had alternating periods of recovery and health impairment. The point prevalence and severity of covid-19 related symptoms also decreased over time, with 18.1% (14.8% to 21.9%) reporting symptoms at 24 months. 8.9% (6.5% to 11.2%) of participants reported symptoms at all four follow-up time points, while in 12.5% (9.8% to 15.9%) symptoms were alternatingly absent and present. Symptom prevalence was higher among individuals who were infected compared with those who were not at six months (adjusted risk difference 17.0% (11.5% to 22.4%)). Excess risk (adjusted risk difference) for individual symptoms among those infected ranged from 2% to 10%, with the highest excess risks observed for altered taste or smell (9.8% (7.7% to 11.8%)), post-exertional malaise (9.4% (6.1% to 12.7%)), fatigue (5.4% (1.2% to 9.5%)), dyspnoea (7.8% (5.2% to 10.4%)), and reduced concentration (8.3% (6.0% to 10.7%)) and memory (5.7% (3.5% to 7.9%)). CONCLUSIONS: Up to 18% of individuals who were not vaccinated before infection had post-covid-19 condition up to two years after infection, with evidence of excess symptom risk compared with controls. Effective interventions are needed to reduce the burden of post-covid-19 condition. Use of multiple outcome measures and consideration of the expected rates of recovery and heterogeneity in symptom trajectories are important in the design and interpretation of clinical trials. REGISTRATIONS: ISRCTN18181860, .

Post COVID-19 condition, work ability and occupational changes in a population-based cohort.

Background: Evidence on the impact of post COVID-19 condition (PCC) on work ability is limited but critical due to its high prevalence among working-age individuals. This study aimed to evaluate the association between PCC, work ability, and occupational changes in a population-based cohort. Methods: We used data from working-age adults included in a prospective, longitudinal cohort of a random sample of all individuals infected with SARS-CoV-2 between August 2020 and January 2021 in the Canton of Zurich, Switzerland. We evaluated current work ability, work ability related to physical and mental demands, and estimated future work ability in 2 years (assessed using Work Ability Index), and PCC-related occupational changes one year after infection. Findings: Of 672 individuals included in this study, 120 (17.9%) were categorised as having PCC (defined as presence of self-reported COVID-19 related symptoms) at 12 months. There was very strong evidence that current work ability scores were mean 0.62 (95% CI 0.30-0.95) points lower among those with PCC compared to those without in adjusted regression analyses. Similarly, there was very strong evidence for lower odds of reporting higher work ability with respect to physical (adjusted odds ratio (aOR) 0.30, 95% CI 0.20-0.46) and mental (aOR 0.40, 0.27-0.62) demands in individuals with PCC. Higher age and history of psychiatric diagnosis were associated with more substantial reductions in current work ability. 5.8% of those with PCC reported direct effects of PCC on their occupational situation, with 1.6% of those with PCC completely dropping out of the workforce. Interpretation: These findings highlight the need for providing support and interdisciplinary interventions to individuals affected by PCC to help them maintain or regain their work ability and productivity. Funding: Federal Office of Public Health, Department of Health of the Canton of Zurich, University of Zurich Foundation, Switzerland; Horizon Europe.

Delivering Safe Surgical Care While Simultaneously Caring for Patients With COVID-19; Assessment of Patient Selection, Volume and Outcomes in a Tertiary Care Hospital.

Objectives: Compare patient selection and postoperative outcomes after surgical treatment for gastrointestinal disorders before and during the SARS-CoV-2 pandemic. Methods: We assessed gastrointestinal surgeries conducted at a tertiary center from 2017-2021 for differences in patient populations and procedures before (up to February 2020) and during the pandemic (March 2020 to December 2021). We analyzed mortality, Intensive Care Unit (ICU) length of stay, admission to ICU and postoperative complications for complex procedures using descriptive statistics and regression models. Results: 7309 procedures were analyzed, showing a caseload reduction in March and October 2020, but no statistical evidence for fewer overall procedures overall. Population characteristics differed with lower Body Mass Indices in 2020 and 2021, more patients smoking and with diabetes treated in 2020. There was no increased mortality, ICU length of stay and in 1,144 complex procedures assessed low overall morbidity at 90 days postoperative. Conclusion: Delivering surgical care while treating patients for COVID-19 in the same hospital was safe. Healthcare officials should consider continuing surgical care during future health crises as consequences of limiting surgical treatment for gastrointestinal disorders may be fatal for patients.

Individual-Level Evaluation of the Exposure Notification Cascade in the SwissCovid Digital Proximity Tracing App: Observational Study.

BACKGROUND: Digital proximity tracing (DPT) aims to complement manual contact tracing (MCT) in identifying exposed contacts and preventing further transmission of SARS-CoV-2 in the population. Although several DPT apps, including SwissCovid, have shown to have promising effects on mitigating the pandemic, several challenges have impeded them from fully achieving the desired results. A key question now relates to how the effectiveness of DPT can be improved, which requires a better understanding of factors influencing its processes. OBJECTIVE: In this study, we aim to provide a detailed examination of the exposure notification (EN) cascade and to evaluate potential contextual influences for successful receipt of an EN and subsequent actions taken by cases and contacts in different exposure settings. METHODS: We used data from 285 pairs of SARS-CoV-2-infected cases and their contacts within an observational cohort study of cases and contacts identified by MCT and enrolled between August 6, 2020, and January 17, 2021, in the canton of Zurich, Switzerland. We surveyed participants with electronic questionnaires. Data were summarized descriptively and stratified by exposure setting. RESULTS: We found that only 79 (58.5%) of 135 contacts using the SwissCovid app whose corresponding cases reported to have triggered the EN also received one. Of these, 18 (22.8%) received the EN before MCT. Compared to those receiving an EN after MCT (61/79, 77.2%), we observed that a higher proportion of contacts receiving an EN before MCT were exposed in nonhousehold settings (11/18, 61.1%, vs 34/61, 55.7%) and their corresponding cases had more frequently reported mild-to-moderate symptoms (14/18, 77.8%, vs 42/61, 68.9%). Of the 18 contacts receiving an EN before MCT, 14 (77.8%) took recommended measures: 12 (66.7%) were tested for SARS-CoV-2, and 7 (38.9%) called the SwissCovid Infoline. In nonhousehold settings, the proportion of contacts taking preventive actions after receiving an EN was higher compared to same-household settings (82%, vs 67%). In addition, 1 (9%) of 11 ENs received in the nonhousehold setting before MCT led to the identification of a SARS-CoV-2-infected case by prompting the contact to get tested. This corresponds to 1 in 85 exposures of a contact to a case in a nonhousehold setting, in which both were app users and the case triggered the EN. CONCLUSIONS: Our descriptive evaluation of the DPT notification cascade provides further evidence that DPT is an important complementary tool in pandemic mitigation, especially in nonhousehold exposure settings. However, the effect of DPT apps can only be exerted if code generation processes are efficient and exposed contacts are willing to undertake preventive actions. This highlights the need to focus efforts on keeping barriers to efficient code generation as low as possible and promoting not only app adoption but also compliance with the recommended measures upon an EN. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number Registry 14990068; https://doi.org/10.1186/ISRCTN14990068.

Mental health of individuals infected with SARS-CoV-2 during mandated isolation and compliance with recommendations-A population-based cohort study.

BACKGROUND: Isolation is an indispensable measure to contain the SARS-CoV-2 virus, but it may have a negative impact on mental health and overall wellbeing. Evidence on the isolation experience, facilitating and complicating factors is needed to mitigate negative effects. METHODS AND FINDINGS: This observational, population-based cohort study enrolled 1547 adults from the general population with SARS-CoV-2 infection reported to authorities between 27 February 2020 and 19 January 2021 in Zurich, Switzerland. We assessed the proportion of individuals reporting symptoms of depression and anxiety before, during and after isolation (by DASS-21), and queried worries, positive experiences, and difficulties. We analyzed the association of these outcomes with socio-demographics using ordinal regression. Additionally, we report free-text statements by participants to capture most important aspects of isolation. The proportion of participants affected by depression or anxiety increased during isolation from 10·0% to 17·1% and 9·1% to 17·6%, respectively. Ordinal regression showed that taking care of children increased the difficulty of isolation (OR 2·10, CI 1·43-3·08) and risk of non-compliance (OR 1·63, CI 1·05-2·53), especially in younger participants. A facilitating factor that individuals commonly expressed was receiving more support during isolation. CONCLUSION: Isolation due to SARS-CoV-2 presents a mental burden, especially for younger individuals and those taking care of children. Public health authorities need to train personnel and draw from community-based resources to provide targeted support, information, and guidance to individuals during isolation. Such efforts could alleviate the negative impact isolation has on the mental and physical health of individuals and ensure compliance of the population with recommendations.

Heterogenous humoral and cellular immune responses with distinct trajectories post-SARS-CoV-2 infection in a population-based cohort.

To better understand the development of SARS-CoV-2-specific immunity over time, a detailed evaluation of humoral and cellular responses is required. Here, we characterize anti-Spike (S) IgA and IgG in a representative population-based cohort of 431 SARS-CoV-2-infected individuals up to 217 days after diagnosis, demonstrating that 85% develop and maintain anti-S responses. In a subsample of 64 participants, we further assess anti-Nucleocapsid (N) IgG, neutralizing antibody activity, and T cell responses to Membrane (M), N, and S proteins. In contrast to S-specific antibody responses, anti-N IgG levels decline substantially over time and neutralizing activity toward Delta and Omicron variants is low to non-existent within just weeks of Wildtype SARS-CoV-2 infection. Virus-specific T cells are detectable in most participants, albeit more variable than antibody responses. Cluster analyses of the co-evolution of antibody and T cell responses within individuals identify five distinct trajectories characterized by specific immune patterns and clinical factors. These findings demonstrate the relevant heterogeneity in humoral and cellular immunity to SARS-CoV-2 while also identifying consistent patterns where antibody and T cell responses may work in a compensatory manner to provide protection.

Burden of post-COVID-19 syndrome and implications for healthcare service planning: A population-based cohort study.

BACKGROUND: Longer-term consequences after SARS-CoV-2 infection are becoming an important burden to societies and healthcare systems. Data on post-COVID-19 syndrome in the general population are required for the timely planning of healthcare services and resources. The objective of this study was to assess the prevalence of impaired health status and physical and mental health symptoms among individuals at least six months after SARS-CoV-2 infection, and to characterize their healthcare utilization. METHODS: This population-based prospective cohort study (Zurich SARS-CoV-2 Cohort) enrolled 431 adults from the general population with polymerase chain reaction-confirmed SARS-CoV-2 infection reported to health authorities between 27 February 2020 and 05 August 2020 in the Canton of Zurich, Switzerland. We evaluated the proportion of individuals reporting not to have fully recovered since SARS-CoV-2 infection, and the proportion reporting fatigue (Fatigue Assessment Scale), dyspnea (mMRC dyspnea scale) or depression (DASS-21) at six to eight months after diagnosis. Furthermore, the proportion of individuals with at least one healthcare contact after their acute illness was evaluated. Multivariable logistic regression models were used to assess factors associated with these main outcomes. RESULTS: Symptoms were present in 385 (89%) participants at diagnosis and 81 (19%) were initially hospitalized. At six to eight months, 111 (26%) reported not having fully recovered. 233 (55%) participants reported symptoms of fatigue, 96 (25%) had at least grade 1 dyspnea, and 111 (26%) had DASS-21 scores indicating symptoms of depression. 170 (40%) participants reported at least one general practitioner visit related to COVID-19 after acute illness, and 10% (8/81) of initially hospitalized individuals were rehospitalized. Individuals that have not fully recovered or suffer from fatigue, dyspnea or depression were more likely to have further healthcare contacts. However, a third of individuals (37/111) that have not fully recovered did not seek further care. CONCLUSIONS: In this population-based study, a relevant proportion of participants suffered from longer-term consequences after SARS-CoV-2 infection. With millions infected across the world, our findings emphasize the need for the timely planning of resources and patient-centered services for post-COVID-19 care.

Adherence and Association of Digital Proximity Tracing App Notifications With Earlier Time to Quarantine: Results From the Zurich SARS-CoV-2 Cohort Study.

Objectives: We aimed to evaluate the effectiveness of the SwissCovid digital proximity tracing (DPT) app in notifying exposed individuals and prompting them to quarantine earlier compared to individuals notified only by manual contact tracing (MCT). Methods: A population-based sample of cases and close contacts from the Zurich SARS-CoV-2 Cohort was surveyed regarding SwissCovid app use and SARS-CoV-2 exposure. We descriptively analyzed app adherence and effectiveness, and evaluated its effects on the time between exposure and quarantine among contacts using stratified multivariable time-to-event analyses. Results: We included 393 SARS-CoV-2 infected cases and 261 close contacts. 62% of cases reported using SwissCovid and among those, 88% received and uploaded a notification code. 71% of close contacts were app users, of which 38% received a warning. Non-household contacts notified by SwissCovid started quarantine 1 day earlier and were more likely to quarantine earlier than those not warned by the app (HR 1.53, 95% CI 1.15-2.03). Conclusion: These findings provide evidence that DPT may reach exposed contacts faster than MCT, with earlier quarantine and potential interruption of SARS-CoV-2 transmission chains.