Time-to-event analysis of factors influencing delay in discharge from a subacute Complex Discharge Unit during the first year of the pandemic (2020) in an Irish tertiary centre hospital

Background: There is a paucity of data investigating delays in discharges from subacute complex care units exclusively dealing with complex cases. Therefore, we aimed to analyse factors causing delays in discharges and explore their implications on the healthcare system in terms of length of stay (LOS), during the COVID-19 pandemic, using time-to-event analysis, to assist in future pandemic healthcare planning decisions. Methods: Single-centre, retrospective, cross-sectional study. Demographics, clinical characteristics and length of stay (LOS) of all patients admitted to our subacute Complex Discharge Unit at our model 4 hospital during the pandemic were retrieved from electronic patient records. The outcome variable in our time-to-event analysis was a delay in discharge with a LOS >15 days. A cox proportional hazards regression model delineated factors contributing to delays. Results: 390 patients were admitted between March 2020 - February 2021 to the subacute complex discharge unit. Among these, 326 (83.6%) patients were >65 years of age, and 233 (59.7%) patients were female. The median (IQR) age was 79 (70-86) years, with a median (IQR) LOS of 19.4 (10-41) days. A total of 237 (60.7%) events were uncensored, LOS > 15 days of which 138 (58.2%) were female, 124 (52.32%) had >4 comorbidities, and 153 (39.2%) were censored into LOS <=15 days and death 19 (4.8%). Kaplan Meier's plot allowed the comparison of factors causing a delay in discharge to single factors: age, gender, and multimorbidity. A multivariate cox regression analysis adjusted to each strata age, gender and MM predicted factors affecting LOS: Age strata 65 - 75 & 75 - 85 [HR 0.233; 95% CI (0.077-.708); p=.010] & [HR .301; 95% CI(.155-.588); p<.001] had common factor patient-centred needs prolonging LOS. The common factors complications arising from comorbidities in male [HR .145; 95 % CI (.081 -.261); p<.001] and female [HR .479; 95% CI (.311 -.737); p<.001], and patient-centred needs in male [HR .472; 95 % CI (.243 -.917); p.027] female [HR .361; 95% CI (.215 -.608); p<.001] exhibited statistically significant results. Conclusion: Reducing LOS is imperative for better patient outcomes and hospital management. The most common factors delaying discharge were complexities that arose from primary diagnoses and patient-centred needs such as cognition, psychosocial needs and carer needs. Further research is needed into exploring multimorbidity as a risk factor for mortality in patients who experience prolonged LOS within a complex discharge unit.

Tackling delays in patient discharge is an ongoing challenge, and with the emergence of the 68 COVID-19 pandemic, there has been a greater strain on the Irish healthcare system. Subacute Home Support Service, or placement or transfer to long-term residential places. Formerly, a 74 delayed discharge was described as a patient deemed medically fit for discharge from an acute 75 bed who remained in the hospital because they were awaiting support or care following 76 discharge.
[6] However, the COVID-19 pandemic has caused disruptions in discharge planning, 77 discontinuity, and incoordination between subacute CDU and community care,[4] due to 78 service curtailment and limited step-down care options. [7] 79 There is a paucity of data investigating discharge delays from a subacute CDU dealing with . CC-BY 4.0 International license It is made available under a perpetuity.
is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. The study was conducted in St James's Hospital (SJH), the largest acute academic teaching 100 model 4 hospital in Ireland, based in the south inner city of Dublin. Within SJH, there is a 23 101 bedded CDU, which specialises in coordinating the safe and effective discharge of medically 102 stable patients. Through early goal-oriented input from multi-disciplinary team members, it is 103 envisaged that the LOS within post-acute CDU does not exceed six weeks. This retrospective, 104 cross-sectional study provides valuable insight into factors contributing to delayed discharges 105 from a subacute CDU, especially during the first year of the COVID-19 pandemic.

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All information was sourced directly from the hospital database via electronic patient records 108 (EPR). In particular, we focused on all adult patients admitted to the CDU, between March delayed discharges. MM was categorised using the Charlson comorbidity index -where 0 was 113 assigned to no comorbidity and 1 for each comorbidity. All details pertaining to delayed 114 discharges were extracted directly from inpatient notes and medical discharge summaries.

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All statistical analyses were conducted using IBM SPSS, version 29. Comparative analysis of 117 LOS between March 2020 -February 2021 was performed using Kaplan Meier for each factor: 118 age, gender, MM, and common reasons for DTOC. Further analyses with COX regressions 119 using multiple covariates were used to identify factors causing delays during the period 120 examined. Patients were compared and analysed by survival analysis, the Kaplan-Meier 121 method was used for single-factor comparison, and the Cox Regression Model was used for 122 multi-factor comparison. The event of interest coded with the value of 1 in our study was 123 delayed discharge; those with LOS<15 days and death were assigned a value of 0 (right 124 censored events). Our main objective was to predict a delay in discharge. With the standard 125 cox regression model, we encountered violations of proportional hazard. Therefore, we used a 126 stratified Cox model allowing for covariates with non-proportional hazard, stratum: age, 127 gender, and MM.

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A total of 390 patients were admitted between March 2020 -February 2021 to the CDU.  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint Each stratum was preliminarily analysed using the Mann-Whitney test and chi-square (Gender) 136 respectively. (Table 1) 137 Insert Table 1 138 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint frailty or falls necessitating integrated rehabilitation, patient-centred needs, and community 149 services against LOS. Patient-centred needs were a significant contributing factor to prolonged LOS >15 days. H) 165 Community services were not a significant factor leading to prolonged LOS > 15 days. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023.  Using stratified COX regression analysis, we analysed age, gender and MM against the five 186 factors associated with delay in discharge. (Table 2) The five main factors discussed were not 187 responsible for delayed LOS in patients >85 years. In a comparison of each stratum to the five 188 main factors causing a delay in discharge, it was noted that complications arising from primary 189 diagnoses and patient-centred needs had statistically significant results p <.05.   is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023.  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10. 1101/2023 Singaporean study that showed how continuity of integrated care in the community was 221 considerably affected during the COVID-19 pandemic. In their study, reluctance or hesitancy 222 from formal and informal caregivers to accept community services due to fear of contracting

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To our knowledge, this is the first study that has investigated the time-to-event analysis of 240 factors influencing delayed discharges, exclusively in complex patients admitted to a CDU 241 during the COVID-19 pandemic. The EPR system used for the study allowed for ease in 242 traceability and transparency of all data. Nevertheless, there were some limitations to the study.

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Our study was conducted in a single centre, explicitly focusing on delaying factors as opposed . CC-BY 4.0 International license It is made available under a perpetuity.
is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint to factors leading to readmission. The study solely focused on patients admitted to the CDU 245 instead of incorporating all hospital admissions and readmissions during the COVID-19 246 pandemic. Third, the interpretation of our findings is limited to the sample size; therefore, the 247 extrapolation and application of data may differ across other centres. Finally, mortality and 248 readmission were not explored in detail during this study. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023.    is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023.  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023.  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint Informed consent and a data protection impact assessment (DPIA) were not required as no 340 identifiable information was collected for the study. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ;https://doi.org/10.1101https://doi.org/10. /2023  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint Additional File 1: Figure S1 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10. 1101/2023 showed an association of at least 4 out of the 5 common delaying factors. Strata Gender 389 exhibited a significant delay in discharge due to complications from comorbidities and patient-390 centred needs; in comparison to the female gender who also experienced a delay in discharge 391 as a result of both factors alongside frailty, falls and/or integrated rehabilitation needs. [A. 392 Complications/comorbidities prolonging discharge, B. Healthcare-associated infection, C. 393 Frailty, falls and/or integrated rehabilitation needs, D. Patient-centred needs, E. Community  is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 5, 2023. ; https://doi.org/10.1101/2023.01.03.23284132 doi: medRxiv preprint