Medical Sciences · Published 2026-07-21 · DOI 10.3390/medsci14030407
Angel Iván Díaz-Salado, Francisco Javier García-Sánchez, Alicia Fuente-Gaforio, Andrés Estropá-Zapater, Irene Pérez-Arévalo, Sandra Moreno-Ruiz, María Teresa Sánchez-Álvarez, Natalia Mudarra-García
Background: The COVID-19 pandemic profoundly disrupted healthcare utilization patterns at both primary care (PC) and hospital emergency department (ED) levels. This study aimed to assess the impact of the pandemic on referral patterns from PC to a hospital ED and on the resource consumption associated with those referrals. Methods: A descriptive, retrospective, longitudinal comparative study with multivariable sensitivity analyses was conducted at a first-level hospital of Madrid (Spain). All consecutive PC-to-ED referrals received during two observation windows were included: a pre-pandemic period (1 June–31 December 2019; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>946</mn></mrow></semantics></math></inline-formula>) and a Later-Pandemic period (1 January–30 June 2022; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>1797</mn></mrow></semantics></math></inline-formula>). Sociodemographic characteristics, referral form quality, diagnostic specialty, and in-ED resource utilization variables were collected and compared using <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>χ</mi><mn>2</mn></msup></semantics></math></inline-formula>, Student’s <i>t</i>-test, and Mann–Whitney U tests as appropriate. To assess seasonal confounding, multivariable logistic and ordinal regression models adjusting for calendar season, age, and sex were performed for the primary resource-utilization outcomes. Results: A total of 2743 referrals were analyzed. The monthly referral rate increased by approximately 122% between periods (135/month vs. 300/month). A statistically significant but clinically negligible difference in mean age was observed (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>53.1</mn><mo>±</mo><mn>18.3</mn></mrow></semantics></math></inline-formula> vs. <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>54.9</mn><mo>±</mo><mn>19.0</mn></mrow></semantics></math></inline-formula> years; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo>=</mo><mn>0.015</mn></mrow></semantics></math></inline-formula>); no significant sex differences were found. Referral form completion improved significantly for clinical history (94.5% vs. 98.2%; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>). Orthopedics referrals nearly tripled (5.8% vs. 18.4%), while respiratory/COVID-19-related referrals represented 22.0% of the 2022 caseload. ED length of stay between 3 and 6 h increased from 13.0% to 42.8% (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>), while the need for urgent blood tests fell from 68.9% to 56.0% (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>), hospital admission from 68.4% to 10.9% (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>), and referral to another center from 12.3% to 0.9% (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>). In multivariable sensitivity analyses, the period effect remained statistically significant after adjustment for calendar season, age, and sex for hospital admission (adjusted OR <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>=</mo><mn>0.062</mn></mrow></semantics></math></inline-formula>; 95% CI: 0.037–0.106; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>) and urgent blood test utilization (adjusted OR <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>=</mo><mn>0.470</mn></mrow></semantics></math></inline-formula>; 95% CI: 0.326–0.678; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>p</mi><mo><</mo><mn>0.001</mn></mrow></semantics></math></inline-formula>), although study period and season remain partly confounded by the non-overlapping design. Conclusions: During the later-pandemic period, PC-to-ED referrals increased substantially while being associated with fewer complementary investigations and fewer hospital admissions. This study documents between-period differences in referral patterns and ED resource utilization rather than causal effects; the differences persisted after adjustment for seasonality but cannot be definitively attributed to the pandemic. Future multi-center longitudinal studies are needed to confirm these trends and clarify their underlying mechanisms.
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Díaz-Salado, A., García-Sánchez, F., Fuente-Gaforio, A., et al. (2026). Impact of the COVID-19 Pandemic on Primary Care Referral Patterns and Resource Utilization in a Hospital Emergency Department: A Comparative Pre- and Later-Pandemic Study. Medical Sciences. https://doi.org/10.3390/medsci14030407