Using claims data from two Japanese cities, we developed and internally validated a multivariable risk prediction model and scoring system to predict the frequent use of emergency house calls. This risk score showed modest discrimination, good calibration, and satisfactory internal validity. It provides a useful and easily applicable tool for identifying high-risk patients who may require frequent emergency house calls in the community. The home health care team should promote understanding of the patient’s disease and prepare for anticipated events for these patients and their families.
Our findings regarding the association between cancer patients and the frequent use of emergency house calls are consistent with a previous study reporting that cancer patients are almost seven times more likely to become frequent attenders at primary care after-hours services compared with non-cancer patients . According to a previous study, cancer in the digestive or respiratory system was the most frequent reason for cancer patients’ use of primary care after-hours services . Another previous study showed that the most common complaints in patients with advanced cancer in the emergency department were pain, shortness of breath, and vomiting, which could also be the reason for emergency house calls . In addition, as “death” is one of the major reasons for emergency house calls in Japan [7, 8], calls due to end-of-life care may be included in cancer patients.
We found that the frequent use of emergency house calls was more likely to occur in patients with high-care need levels. This finding may be explained as follows: Higher level of care needed is associated with fever events, and fever is a significant reason for emergency house calls . A previous study in Japan found that fever was more likely in patients with care need levels ≥3 than ≤2, and the conditions most likely to cause fever were pneumonia/bronchitis, skin and soft tissue infections, and urinary tract infections . The authors explained that this was due to an increased risk of aspiration because of decreased strength to cough and increased susceptibility to infections caused by decreased muscle strength and poor nutritional status.
Home oxygen use was associated with the frequent use of emergency house calls. This is consistent with a study in Japan in which dyspnea was a common chief complaint and there was an association between emergency house calls for dyspnea and home oxygen use . Another study has shown that chronic obstructive pulmonary disease (COPD) is more prevalent among those requiring frequent primary care after-hours services and that complications and exacerbations of chronic diseases are the reasons for this help-seeking behavior .
This risk score would be useful to allocate medical resources and maintain a home healthcare system in the community. In Japan, a revision of the medical fee schedule introduced HCSCs with home care support functions available 24-hour a day until the patient dies, which enabled 24-hour home visit care at the patient’s request in 2006 . In 2012, enhanced HCSCs, which required the appointment of three or more full-time doctors, were institutionalized. Although the number of HCSCs facilities is increasing, enhanced HCSC accounts for only a small percentage of the total HCSC (approximately 24% in 2018) . Moreover, many general clinics do not meet HCSC requirements while providing home visits . Most of these clinics are in solo practice and have difficulties providing three or more full-time doctors . Therefore, our tool would be helpful to identify high-risk patients who may require the frequent use of emergency house calls and reduce the burden on primary care physicians, especially for solo practitioners, by associating high-risk patients to well-staffed medical institutions, such as enhanced HCSCs.
Our tool is based on information readily available in a primary care setting. Therefore, this score can indicate the risk at the start of the regular home visits to allow targeting a timely approach for high-risk patients. Furthermore, because this score contains only three factors, it is easy to remember and can be quickly calculated in clinical practice.
To the best of our knowledge, this is the first study to develop a risk prediction model for the frequent use of emergency house calls among older people who receive regular home visits. However, this study has several limitations. First, we did not externally validate the proposed model; further validation in different populations is warranted. Second, we did not examine some potential predictors that are known risk-factors, such as the urethral catheter placement , because information on these factors was not available. Third, some clinical information generally obtained in clinical settings (such as symptoms, laboratory data, and imaging findings) was unavailable in the database. Fourth, although the instances in which patients and their families perceive the need to request emergency house calls may be influenced by appropriate symptom management, enhanced home health care, palliative care with team coordination, and family caregiver education and support, we were unable to consider these factors. These factors should be included to improve risk score performance in future studies.