Abstract
This cohort study investigates trends in emergency department (ED) visits and hospital admissions from EDs in California by visit acuity from 2012 to 2022.
Introduction
Emergency departments (EDs) are an integral component of the US health care system, as they care for all patients and provide an entry point.1 However, ED visits have outpaced population growth while the number of EDs has decreased.2 Between 2011 and 2021, California ED visits increased by 7.4% while the number of EDs decreased by 3.8%.2 Furthermore, from 2006 to 2019, high complexity treat-and-release ED visits billed as high intensity increased from 4.8% to 19.2% nationally.3
Knowing the proportion of ED visits by acuity resulting in hospital admission may provide benchmarking trends for adequate hospital capacity and planning. Therefore, we investigated trends in California ED visits and hospital admissions from EDs by acuity from January 1, 2012, to December 31, 2022.
Methods
This retrospective cohort study used publicly available ED visit data from the California Department of Healthcare Access and Information (HCAI), which mandates reporting from all hospitals in California.4 The University of California, San Francisco, Institutional Review Board approved the study and waived the need for informed consent owing to the use of publicly available data. The study followed the STROBE reporting guideline.
We defined ED visit acuity using Current Procedural Technology (CPT) codes based on classifications from the California HCAI. We stratified ED visits as nonurgent (99281), urgent (99282), moderate (99283), severe (99284), and critical (99285 and 99291) and as resulting in discharge or hospital admission. Data were analyzed using R, version 4.1 (R Project for Statistical Computing). Changes in the proportion of visits by CPT code were assessed with a χ2 trend test, and linear patterns in visits and admission were assessed using linear regression models. Two-sided P < .05 indicated statistical significance.
Results
The overall number of ED visits grew from 12.5 to 14.3 million from 2012 to 2022 (14.0% [95% CI, 2.3%-28.7%]) (Table). During the study period, nonurgent visits decreased by −55.2% (95% CI, −61.3% to −47.0%) (Figure), whereas severe visits increased by 34.8% (95% CI, 20.9%-52.3%), and critical visits increased by 75.8% (95% CI, 62.5%-91.4%).
Table. ED Visits and Hospital Admissions From EDs by Visit Acuity, 2012 to 2022.
| ED visit acuity (CPT code) | Study year | Change 2012 to 2022, % (95% CI) | P valuea | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | |||
| ED visits, No. | |||||||||||||
| Nonurgent (99281) | 796 173 | 800 986 | 801 400 | 808 106 | 776 707 | 733 601 | 703 543 | 450 142 | 316 722 | 336 071 | 356 464 | −55.2 (−61.3 to 47.0) | <.001 |
| Urgent (99282) | 2 014 199 | 2 045 532 | 2 065 657 | 2 170 099 | 2 262 902 | 2 103 459 | 2 058 891 | 1 826 148 | 1 310 505 | 1 520 222 | 1 652 470 | −18.0 (−27.9 to −4.8) | .01 |
| Moderate (99283) | 4 492 906 | 4 684 705 | 4 884 701 | 5 191 179 | 5 315 877 | 5 433 919 | 5 074 777 | 4 749 307 | 3 643 358 | 3 848 953 | 4 440 223 | −1.2 (−16.6 to 14.3) | .17 |
| Severe (99284) | 3 063 915 | 3 101 587 | 3 349 631 | 3 550 280 | 3 595 306 | 3 808 953 | 3 793 604 | 4 399 317 | 3 434 760 | 3 799 651 | 4 130 943 | 34.8 (20.9 to 52.3) | .006 |
| Critical (99285 and 99291) | 2 040 242 | 1 986 544 | 2 260 799 | 2 404 990 | 2 537 614 | 2 756 110 | 3 057 700 | 3 374 000 | 3 084 971 | 3 375 539 | 3 586 523 | 75.8 (62.5 to 91.4) | <.001 |
| Totalb | 12 505 718 | 12 722 085 | 13 436 083 | 14 198 173 | 14 560 356 | 14 928 933 | 14 781 546 | 14 876 653 | 11 860 597 | 12 944 692 | 14256171 | 14.0 (2.3 to 28.7) | .60 |
| Hospital admissions from EDs, No. | |||||||||||||
| Nonurgent (99281) | 8467 | 5271 | 6531 | 4361 | 6556 | 3527 | 3855 | 2838 | 5764 | 7330 | 1616 | −80.9 (−85.1 to −73.4) | .12 |
| Urgent (99282) | 18 166 | 16 946 | 26 000 | 22 343 | 22 196 | 12 992 | 10 516 | 16 450 | 21 792 | 32 006 | 10 040 | −44.7 (−62.9 to 8.5) | .83 |
| Moderate (99283) | 152 571 | 159 505 | 184 464 | 171 230 | 222 980 | 190 795 | 136 946 | 147 554 | 157 194 | 170 265 | 156 051 | 2.3 (−15.2 to 28.9) | .57 |
| Severe (99284) | 473 478 | 481 497 | 459 033 | 437 579 | 419 558 | 382 578 | 319 464 | 355 526 | 324 235 | 381 340 | 333 236 | −29.6 (−34.8 to −23.5) | <.001 |
| Critical (99285 and 99291) | 1 075 460 | 1 054 890 | 1 095 615 | 1 149 611 | 1 173 720 | 1 249 622 | 1 332 966 | 1 332 997 | 1 259 379 | 1 326 255 | 1 345 735 | 25.1 (19.0 to 31.9) | <.001 |
| Total | 1 728 142 | 1 718 109 | 1 771 643 | 1 785 124 | 1 845 010 | 1 839 514 | 1 803 747 | 1 855 365 | 1 768 364 | 1 917 196 | 1 936 226 | 12.0 (8.6 to 15.7) | .002 |
| Hospital admissions from EDs, % | |||||||||||||
| Nonurgent (99281) | 1.1 | 0.7 | 0.8 | 0.5 | 0.8 | 0.5 | 0.5 | 0.6 | 1.8 | 2.2 | 0.5 | −57.4 (−74.7 to 34.8) | .35 |
| Urgent (99282) | 0.9 | 0.8 | 1.3 | 1.0 | 1.0 | 0.6 | 0.5 | 0.9 | 1.7 | 2.1 | 0.6 | −32.6 (−60.1 to 115) | .44 |
| Moderate (99283) | 3.4 | 3.4 | 3.8 | 3.3 | 4.2 | 3.5 | 2.7 | 3.1 | 4.3 | 4.4 | 3.5 | 3.5 (−13.9 to 29.7) | .46 |
| Severe (99284) | 15.5 | 15.5 | 13.7 | 12.3 | 11.7 | 10.0 | 8.4 | 8.1 | 9.4 | 10.0 | 8.1 | −47.8 (−52.7 to −41.8) | <.001 |
| Critical (99285 and 99291) | 52.7 | 53.1 | 48.5 | 47.8 | 46.3 | 45.3 | 43.6 | 39.5 | 40.8 | 39.3 | 37.5 | −28.8 (−30.7 to −26.8) | <.001 |
Abbreviations: CPT, Current Procedural Terminology; ED, emergency department.
P values are related to testing for linear trend.
Totals do not equal the sum by acuity due to visits missing CPT codes.
Figure. Emergency Department Visits by Acuity.
Acuity is expressed as Current Procedural Terminology codes (given parenthetically).
Likewise, the annual number of ED visits resulting in hospital admission increased by 12.0% (95% CI, 8.6%-15.7%). This increase was not equally distributed by acuity. The proportion of hospital admissions from nonurgent ED visits decreased from 1.1% in 2012 to 0.5% in 2022 (−54.5% [95% CI, −74.7% to −34.8%]). Notably, the proportion of hospital admissions from severe ED visits decreased from 15.5% in 2012 to 8.1% in 2022 (−47.8% [95% CI, −52.7% to −41.8%]), even as the proportion of these ED visits increased in that time. The proportion of critical ED visits resulting in admission decreased from 52.7% in 2012 to 37.5% in 2022 (−28.8% [95% CI, −30.7% to −26.8%]).
Discussion
We found that from 2012 to 2022, the increase in severe and critical ED visits outpaced corresponding rates of hospital admissions from EDs. Severe visits rose by 34.8% and critical visits by 75.8%, aligning with findings of previous studies5 and suggesting that patients may be presenting with higher-acuity conditions. However, this observed rise in high-acuity ED visits was not met by a rise in hospital admissions; the proportion of severe and critical ED visits resulting in admission decreased from 15.5% to 8.1% and from 52.7% to 37.5%, respectively.
The findings of this cohort study raise questions about whether the increase in high-acuity ED visits can be fully explained by sicker patients or whether external factors (eg, more stringent hospital admissions criteria, changing demographics, and shifting practice patterns3,6) and/or upcoding (ie, documenting lower-acuity visits as higher-acuity, yielding higher payout) are substantial contributors. Study limitations include our use of administrative data, which do not have the granularity of clinical data or medical charts. These findings may inform policy makers and health care stakeholders when determining ED funding and resource allocation.
Data Sharing Statement
References
- 1.Fields WW, Asplin BR, Larkin GL, et al. The Emergency Medical Treatment and Labor Act as a federal health care safety net program. Acad Emerg Med. 2001;8(11):1064-1069. doi: 10.1111/j.1553-2712.2001.tb01116.x [DOI] [PubMed] [Google Scholar]
- 2.Hsia RY, Zagorov S, Sarkar N, Savides MT, Feldmeier M, Addo N. Patterns in patient encounters and emergency department capacity in California, 2011-2021. JAMA Netw Open. 2023;6(6):e2319438. doi: 10.1001/jamanetworkopen.2023.19438 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Janke AT, Gettel C, Koski-Vacirca R, Lin MP, Kocher KE, Venkatesh AK. Trends in treat-and-release emergency care visits with high-intensity billing in the US, 2006-19. Health Aff (Millwood). 2022;41(12):1772-1780. doi: 10.1377/hlthaff.2022.00484 [DOI] [PubMed] [Google Scholar]
- 4.Department of Health Care Access and Information, California Health and Human Services . Hospital annual utilization report & pivot tables. Updated October 27, 2023. Accessed October 27, 2023. https://data.chhs.ca.gov/dataset/hospital-annual-utilization-report
- 5.Hsia RY, Sabbagh SH, Guo J, Nuckton TJ, Niedzwiecki MJ. Trends in the utilisation of emergency departments in California, 2005-2015: a retrospective analysis. BMJ Open. 2018;8(7):e021392. doi: 10.1136/bmjopen-2017-021392 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Pitts SR. Higher-complexity ED billing codes—sicker patients, more intensive practice, or improper payments? N Engl J Med. 2012;367(26):2465-2467. doi: 10.1056/NEJMp1211315 [DOI] [PubMed] [Google Scholar]
Associated Data
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Supplementary Materials
Data Sharing Statement
