Challenges of one-year longitudinal follow-up of a prospective, observational cohort study using an anonymised database: recommendations for trainee research collaboratives

Abstract

BackgroundTrainee research collaboratives (TRCs) have pioneered high quality, prospective ‘snap-shot’ surgical cohort studies in the UK. Outcomes After Kidney injury in Surgery (OAKS) was the first TRC cohort study to attempt to collect one-year follow-up data. The aims of this study were to evaluate one-year follow-up and data completion rates, and to identify factors associated with improved follow-up rates.MethodsIn this multicentre study, patients undergoing major gastrointestinal surgery were prospectively identified and followed up at one-year following surgery for six clinical outcomes. The primary outcome for this report was the follow-up rate for mortality at 1 year. The secondary outcome was the data completeness rate in those patients who were followed-up. An electronic survey was disseminated to investigators to identify strategies associated with improved follow-up.ResultsOf the 173 centres that collected baseline data, 126 centres registered to participate in one-year follow-up. Overall 62.3% (3482/5585) of patients were followed-up at 1 year; in centres registered to collect one-year outcomes, the follow-up rate was 82.6% (3482/4213). There were no differences in sex, comorbidity, operative urgency, or 7-day postoperative AKI rate between patients who were lost to follow-up and those who were successfully followed-up. In centres registered to collect one-year follow-up outcomes, overall data completeness was 83.1%, with 57.9% (73/126) of centres having ≥95% data completeness. Factors associated with increased likelihood of achieving ≥95% data completeness were total number of patients to be followed-up (77.4% in centres with < 15 patients, 59.0% with 15–29 patients, 51.4% with 30–59 patients, and 36.8% with > 60 patients, p = 0.030), and central versus local storage of patient identifiers (72.5% vs 48.0%, respectively, p = 0.006).ConclusionsTRC methodology can be used to follow-up patients identified in prospective cohort studies at one-year. Follow-up rates are maximized by central storage of patient identifiers.

Preoperative geriatric nutritional risk index and neutrophil-to-lymphocyte ratio relate to postoperative acute kidney injury in elderly patients undergoing laparoscopic abdominal surgery

“…This study delves into the comparisons of preoperative GNRI and NLR between the AKI and NAKI groups. The substantial decrease in preoperative GNRI and the notable increase in NLR among AKI patients are consistent with the study’s hypothesis and align with existing literature linking poor nutritional status and heightened inflammatory response to adverse postoperative outcomes, including AKI ( 23 ).…”

Impact of postoperative acute kidney injury in patients undergoing major gastrointestinal surgery on 1-year survival and renal outcomes: a national multicentre cohort study

“…First, there was a moderate attrition of patients from recruitment to 1-year follow-up. However, this was largely related to centre non-participation and there was no suggestion of residual attrition bias 18 . The high rate of open surgery included may explain the marginally higher rates of malignant pathology and major 30-day postoperative complications observed compared with the original cohort.…”

“…To facilitate changes in research team members over the 1-year interval from recruitment to follow-up, patient-identification numbers were stored centrally using a secure REDCap (Research Electronic Data Capture) server 17 , or on a password-protected NHS computer according to local Caldicott Guardian requirement. The full methodology for long-term follow-up in this study has been reported previously 18 . In brief, all participating centres were invited to submit 1-year follow-up data for patients included in the original cohort study.…”

“…It was preplanned to explore any impact of attrition bias through comparing patient, disease and operation factors of patients retained within 1-year follow-up versus those with no outcome data available. Full exploration of the effects of attrition within this study methodology has been described previously 18 .…”

Preoperative nasopharyngeal swab testing and postoperative pulmonary complications in patients undergoing elective surgery during the SARS-CoV-2 pandemic

“…Studies adopting this collaborative cohort study methodology have achieved high levels of case ascertainment and data accuracy with external validation 15 , 16 . In the present study, low-volume centres (fewer than 5 patients per specialty group) were identified, and reviewed independently to confirm complete case ascertainment.…”