This study was reviewed and approved by the Texas Christian University Institutional Review Board (IRB; IRB #2023-422). The requirement for informed consent was waived because this was a retrospective chart review involving existing electronic health record (EHR) data with no direct patient contact and minimal risk to participants. All study procedures were conducted in accordance with the ethical principles of the Declaration of Helsinki and applicable institutional and regulatory guidelines.

We conducted a retrospective descriptive case-series study evaluating a hybrid house-call model for the management of adults with pneumonia. EHRs from a tertiary care center and affiliated hybrid house-call practice in North Texas were reviewed for encounters occurring between January 1, 2022, and January 1, 2024. The primary objective was to assess outpatient pneumonia management through this care model by describing patient characteristics, use patterns, and ED referral rates. Patient records were identified using the following International Classification of Diseases, 10th Revision (ICD-10) diagnosis codes related to pneumonia: J18.9 (pneumonia and unspecified organism), J15.8 (other bacterial pneumonia), J16.8 (pneumonia due to other specified infectious organisms), J17 (pneumonia in diseases classified elsewhere), and J18.1 (lobar pneumonia and unspecified organism). Eligible participants were adults (aged ≥18 years) with a documented diagnosis of pneumonia identified by one of the predefined ICD-10 codes, who were evaluated through the hybrid house-call program during the study period. Patients aged <18 years or without sufficient documentation to confirm a pneumonia diagnosis were excluded. Records lacking sufficient information to confirm a pneumonia diagnosis were excluded prior to analysis. For the remaining cohort, analyses were conducted using complete-case data, and no imputation of missing values was performed. All data were handled in a secure manner, and only deidentified data were used for analysis to protect participant confidentiality.

Patients received evaluation through a hybrid house-call model consisting of an in-home visit performed by a trained health care professional in conjunction with real-time physician oversight using telemedicine. Clinical assessment included medical history taking, physical examination, vital signs recording, and point-of-care evaluation when indicated. On the basis of clinical judgment, patients were managed at home with treatment, scheduled for follow-up, or referred to the ED when a higher level of care was deemed necessary.

All patient records were anonymized prior to analysis. Extracted variables included patient demographics (age and sex), the total number of visits per patient, visit type (hybrid house call vs other), treatments administered, comorbidities, CRB-65 (confusion, respiratory rate, blood pressure, age ≥65 years) score [14,15], ED referral, and rural residence. The primary outcomes were the proportion of patients successfully managed without ED referral and the use of the hybrid house-call model (total number of visits). Secondary outcomes included CRB-65 severity distribution, comorbidity burden, and the characteristics of patients requiring ED referral.

Because blood urea nitrogen measurements were not consistently available at the index encounter, illness severity was assessed using the CRB-65 score rather than the CURB-65 (confusion, urea, respiratory rate, blood pressure, age ≥65 years) score. CRB-65 assigns 1 point each for new-onset confusion, respiratory rate ≥30 breaths per minute, systolic blood pressure <90 mm Hg or diastolic blood pressure ≤60 mm Hg, and age ≥65 years. Scores range from 0 to 4, with higher scores indicating greater predicted mortality risk. Clinical variables were abstracted from documentation recorded during the index clinical encounter, defined as the first eligible encounter during the study period in which one of the predefined pneumonia ICD-10 diagnosis codes was assigned [16].

Data were entered into Microsoft Excel [17] for analysis. Descriptive statistics were used to summarize patient characteristics, the number of visits per patient, CRB-65 scores, ED referral rates, and treatment patterns. Continuous variables are reported as means (SDs) or medians (IQRs), as appropriate, and categorical variables are reported as frequencies and percentages. Frequency distributions were used to categorize CRB-65 scores. Rural residences were determined using the Health Resources and Services Administration Rural Health Grants Eligibility Analyzer [18]. Patients referred to the ED were further stratified according to comorbidities and CRB-65 scores to descriptively characterize referral patterns. The patient served as the primary unit of analysis. For patients with multiple encounters, visit-level data were aggregated to summarize health care use, while patient-level outcomes were analyzed once per individual.

Continuous variables are presented as means (SDs) or medians (IQRs), as appropriate. Categorical variables are presented as frequencies and percentages. Because CRB-65 scores were ordinal and not normally distributed, differences between patients referred to the ED and those managed without ED referral were evaluated using the Mann-Whitney U test. Statistical significance was defined as P<.05. Analyses were performed using Python (version 3.13.7) with the SciPy library.

A total of 30 patient records were screened for eligibility (Figure 1). Two records were excluded: one involved a patient aged <18 years and the other lacked sufficient documentation to confirm a pneumonia diagnosis. The final analytic cohort therefore included 28 adult patients. Of these, 8 (28.6%) were male and 20 (71.4%) were female. The mean age was 58.9 (SD 21.8) years. Of the 28 patients, 14 (50%) patients resided in areas classified as rural (Table 1).

During the 2-year study period, 28 patients accounted for 56 clinical encounters. The median number of encounters per patient was 2 (IQR 1-3; range 1-7). Most patients initiated care through the hybrid house-call model (24/28, 85.7%), whereas 3 (10.7%) patients initiated care through a virtual visit and 1 (3.6%) patient initiated care through an in-clinic visit.

Of the 28 patients, 19 (67.9%) had documented insurance coverage, whereas 9 (32.1%) had no insurance on file. Of the 8 patients recommended for ED transfer, 2 were uninsured. Among the insured patients, 8 were covered through government-funded programs, including Medicare or WellMed [19], whereas 11 had private insurance coverage.

Over the 2-year study period, 28 patients accounted for 56 clinical encounters (median 2, IQR 1-3 encounters per patient). Of the 28 patients, 24 (85.7%) patients initiated care through the hybrid house-call model, 3 (10.7%) through virtual visits, and 1 (3.6%) through an in-clinic visit. In total, 8 (28.6%) patients were referred to the ED, all of whom had documented comorbidities.

CRB-65 scores ranged from 0 to 2. Overall, 13 (46.4%) patients had a CRB-65 score of 0, a total of 13 (46.4%) had a score of 1, and 2 (7.1%) had a score of 2. Patients referred to the ED had significantly higher CRB-65 scores than those managed without ED referral (median 1, IQR 1-1.5 vs median 0, IQR 0-1; Mann-Whitney U=34.0; P=.01; Figure 2 and Table 2).

In this retrospective descriptive case-series study, patients referred to the ED had significantly higher CRB-65 scores than those managed without ED referral, suggesting greater illness severity among patients requiring escalation of care. Most patients were managed without ED referral, whereas patients requiring escalation had higher illness severity and documented comorbidities. Although this pilot study was not designed to evaluate clinical outcomes or safety, these findings provide insight into ED referral patterns according to documented illness severity within the hybrid care model. These findings should be interpreted within the context of a small, real-world descriptive case-series study.

Our findings are consistent with previous literature demonstrating that alternative acute care models, including urgent care centers and telemedicine, may reduce ED use for lower-acuity conditions [20-23]. The hybrid house-call model extends this concept by combining in-home clinical assessment with physician oversight through telemedicine. This approach allows patients with suspected pneumonia to receive timely evaluation at home while providing a mechanism for referral to the ED when clinically necessary. Because downstream ED visits, hospitalization, readmission, and mortality were not assessed, the effectiveness or safety of this care model cannot be determined from the present study.

Patients referred to the ED had significantly higher CRB-65 scores than those managed without ED referral, demonstrating an association between documented illness severity and ED referral decisions. Although CRB-65 provides a standardized approach to pneumonia risk stratification, referral decisions in the present study also incorporated clinician judgment and patient-specific factors, including comorbidities. Prior studies have similarly emphasized that pneumonia severity scores should complement rather than replace clinical judgment when determining the appropriate site of care [24]. Future prospective studies should evaluate hybrid care models using standardized severity assessments together with longitudinal patient outcomes and patient-centered measures.

This study has several limitations. First, the small sample size, retrospective design, and single-region setting may limit the generalizability of the findings. Second, because this was a retrospective descriptive case-series study, we were unable to determine downstream clinical outcomes, including ED presentation, hospitalization, readmission, or mortality, precluding assessment of the safety or effectiveness of outpatient management. Additionally, ED referral decisions reflected clinician judgment and patient-specific factors rather than a standardized CRB-65–based referral protocol. Third, illness severity was assessed using the CRB-65 score because contemporaneous blood urea nitrogen measurements were not consistently available in the EHR. Although CRB-65 is an established tool for community-based pneumonia risk assessment, it may underestimate illness severity compared with CURB-65 in some patients. Despite these limitations, this study represents, to our knowledge, the first evaluation of a hybrid telemedicine–house-call model for pneumonia management. These findings provide preliminary evidence supporting this care model and may inform future multicenter prospective studies evaluating its effectiveness, scalability, and economic impact.

This retrospective pilot study demonstrates the use of a hybrid telemedicine–house-call model for the outpatient evaluation of adults with pneumonia in a real-world clinical setting. Patients referred to the ED had higher CRB-65 scores than those managed without ED referral, demonstrating an association between higher documented CRB-65 scores and ED referral. Because this descriptive case-series study lacked a comparison group and did not assess downstream clinical outcomes, no conclusions can be drawn regarding the effectiveness, safety, or impact of the model on ED use. Prospective comparative studies with longitudinal follow-up are needed to evaluate these outcomes.