The impact of daylight and window views on length of stay among patients with heart disease: A retrospective study in a cardiac intensive care unit

Why does this study matter?
The authors start the paper by highlighting the prevalence of heart disease, the use of LOS as a clinical outcome measure, and the inherent risk of adverse events associated with stays in ICUs and CICUs. That all matters. But for me, when we get into the world of evidence-based design for healthcare, everyone hears about Roger Ulrich’s seminal study from 1984 – the window with a view. It’s hard to believe the study is almost 40 years old now! I’ve always wondered, in today’s world, with shorter stays and advanced clinical techniques, does this type of result hold? Ulrich’s study used patients with gall bladder surgery. They were in the hospital for days. Today that’s an outpatient procedure. This study isn’t exactly a replication of Ulrich’s work, but it builds on that premise, and the authors have taken a different setting and a slightly different approach with the data analysis.

How was the study done?
In this study, an institutional database was used to gather 4 years of data for patients directly admitted into a 15-room CICU, in an urban location, in South Carolina. Patients had been admitted for a heart attack or a few other related diagnoses. The unit has three room types, making it the perfect natural experiment. Two rooms faced south, with full-length windows parallel to the bed. The room with a view. In this study, the view was an urban skyline, not the wooded area we know from the Ulrich study.

The unit also has six south-facing rooms with the bed perpendicular to the window, so daylight coming in behind the patient’s head, but no view. And seven rooms with no window. The analysis included patient characteristics like severity of illness and risk of mortality. Demographic information, the admission source and status, DRGs, and clinical characteristics were also incorporated into a generalized linear model to examine the influence of room type on LOS, while accounting for any of these potentially confounding factors. Patients were also categorized according to a typical length of stay - 3 days or less, or a more prolonged stay. Sensitivity analysis was conducted for these subset populations.     
 

So what do we learn from the study?
There were differences when looking at all patients, but even though the shortest stay was in Room A and the longest in Room C, there results were not significant from a statistical perspective.
The authors did find that overall, LOS was significantly shorter among intubated patients in Room type A compared to Room type C.   

In reviewing the sensitivity analysis for patients with a stay of 3 days or less, the results showed there were significant differences in LOS depending on being in the room with a view or the room with no windows. The difference was close to a full day – 19.2 hours less.  While the LOS for the room with daylight only was in between the other 2 rooms, it was not significantly different from either.

With respect to the clinical influences found through the sensitivity analysis:

• Intubated patients stayed significantly less time in rooms with access to a view (Room A) compared to rooms with no windows (Room C).
• Patients with delirium stayed less time in the rooms providing views and daylight alone (Rooms A and B) compared to the room with no window.
• Patients with anxiety stayed less time in Room A compared to both Room types B and C. This ties into Ulrich’s theory of supportive design that links reduced anxiety and stress to natural elements. This ties into the next findings.

There are relationships between anxiety and obesity and anxiety and dementia among heart patients. In this study, patients with obesity or dementia, also stayed less time in Room type A compared to the other room types. The study also found that patients receiving palliative care had a significantly decreased LOS in Room type A compared to Room types B and C.

Can we say the results are definitive?
This was a based on a small number of rooms on a single floor in a single hospital so that’s certainly a limitation. We don’t know how generalizable the results are, but the authors indicate that the nature of the data suggests the results could likely be applied to other “CICUs with patients experiencing what was defined here as a typical length of stay. That 3-day cutoff was based on the literature and the nature of the data from this site, but it might vary for other sites. Because of a smaller sample size of patients with a prolonged stay, as well as differences in that population, the sensitivity analysis was only conducted for the typical stay.

What’s the takeaway?
I will admit that this study didn’t catch my eye when it was first published, so I regret that I didn’t see the light, so to speak. That said, it’s such a neatly packaged natural experiment that comes with some novel and rigorous analysis, so the authors have taken the topic to a new level. In the end, we learn that daylight is still important for recovery, and moreover, we learn more about the importance of the view. 

Summary of:
Jafarifiroozabadi, R., Joseph, A., Bridges, W., & Franks, A. (2023). The impact of daylight and window views on length of stay among patients with heart disease: A retrospective study in a cardiac intensive care unit. Journal of Intensive Medicine, 3(2), 155–164. https://doi.org/10.1016/j.jointm.2022.11.002

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