The present retrospective study investigated the national-level CLP service in general hospitals in Japan, using a national inpatient database. The present study characterized (1) the key overview of patients who received CLP services and (2) the geographic disparity of these patients. To the best of our knowledge, this article is one of the first reports revealing CLP disparity. In today’s current health care climate of cost savings, limited allocation of resources, and expectations of demonstrations of the value of services and clinical productivity, it is important to clarify the current situation regarding CLP services to understand how to make for future improvements to the healthcare system.
After the introduction of CLP services in 2012, the provision of CLP was consistently increased (Table 1), implying the recognition of the need for CLP services in medical and surgical patients. Also, almost 70% of patients we studied who received CLP services were over the age of 65 in 2016, which was much higher than in recent studies in a Canadian setting (roughly 42% from two academic tertiary care hospitals) (21) and an Italian setting (mean and SD age was 57.9 ±19.4 from one general hospital) which were in line with other reports from Europe in terms of demographic data (about 41%) (22). We speculated that this is due to the difference in the aging ratio of the study population, criteria for referral, priority/availability for CLP referral, and the healthcare system. Our results also showed that about 70 percent of CLP services were provided to patients whose admittance was unplanned or who were admitted due to an urgent condition. This is partly because such patients may not have been prepared for, or may be especially agitated about, their health problems compared with planned admission patients.
While data regarding discharge settings and outcomes were usually unavailable internationally, it was reasonable that about three out of every ten patients who received CLP were transferred to other hospitals (Table 1), which is much higher than the 5.8–7.5% overall average of acute-/mixed-care inpatients in a Japanese setting (23). We speculated that some of the patients with psychiatric comorbidities were transferred to psychiatric hospitals (detailed data about discharge settings were not available). It was surprising that about nine percent of patients who received CLP services were discharged as dead (Table 1), which was also much higher than the overall average of 1.7%–3.3% (24). We also speculated that some CLP services were provided for severe patients who needed psychiatric support for improving their mental condition as a part of end-of-life care. However, further studies are required to address this issue due to data unavailability.
It was reasonable that more than one-fifth of CLP services were provided to the cancer patients, considering both the number of cancer inpatients (13.4% in general hospitals) (25) and that approximately 29–43% of these patients fulfilled the diagnostic criteria for having a psychiatric disorder (26, 27) (Table 2). However, in terms of international comparisons of CLP data, it is not easy to compare in detail. For example, few data were available in the basic disease classifications of the study cohorts. Even if data were shown, as in the Canadian study (21), it may not be easy to compare with our data due to the absence of consensus in disease classifications for CLP cases. Another example is that our data pertaining to the reasons for CLP referrals (psychiatric diagnosis) are not available, as they were for a previous study (21, 28), because the DPC database was not designed for specific studies but various research fields. Further efforts for international collaborative research will help improve the quality of available evidence.
Almost 70% of patients who received CLP services used in-hospital psychotherapy; the rests did not use in-hospital psychotherapy (Appendix 1). This is partly because some CLP services were provided to patients with postoperative delirium which usually disappeared in a short period (i.e., a week), who usually did not need in-hospital psychotherapy. Although the distribution of the number of provided in-hospital psychotherapy sessions was right-skewed, there was another peak in “six and over” during hospitalization. These patients would be those with severe psychiatric conditions or longer lengths of stay. Another possibility is that there was a lack of in-hospital psychiatry in some cases, especially in hospitals where psychiatric healthcare resources are scarce. This is one of the further questions to be addressed.
CLP in Japan started from selected prefectures and gradually spread throughout Japan; however, there are still 14 prefectures where provided no CLP services with their own in 2016 (Figure 1). In addition, there is a variation in providing CLP services even in the regions (Table 3). Although 5 years had passed from the introduction of CLP, there is still geographical disparity of CLP services, which needs to be improved. It is similar in the United Kingdom, where studies identified widespread availability of liaison psychiatry services in acute care hospitals (29). Investigation in the current/future needs of CLPs and enhancing/expanding the delivery system of CLPs would be considerable. Further efforts for improving geographic disparity is needed for achieving efficient care in CLP services for those who needed care.
This study has major strengths: it is the largest reported study on this subject in terms of patient numbers in a Japanese setting based on a national administrative database. According to the National Database Open Data, the analysis covered more than 92% of the CLPs in Japan (30). Further, to our knowledge, this study was the first report which reveals fundamental information of CLP services and geographic disparity in CLP services in Japanese setting which were essential for enhancing the quality of life of patients and improving efficiency in the healthcare delivery system. Thus, our results could inform future interventions to improve medical services and the provision of healthcare.
Several limitations of the present study must be considered. First, this investigation was based on an administrative database (DPC). The database covers more than 93% of CLP services conducted across Japan; however, a few hospitals do not participate in the DPC/PDPS system and the exclusion of these hospitals may have introduced an element of sampling bias.
Second, data pertaining to several important variables are not available in the DPC database. Therefore, factors such as the difference in psychiatric diagnosis before and after CLP, reason for CLP referral, timing of CLP, detailed interventions in CLPs, and degree of psychiatrists’ proficiency were not included in the analysis.
Third, the present study did not analyze patient outcomes. Although previous researches had reported the benefit of CLP services (10-14), further outcome studies based on a DPC database would be preferred.