In this study, patient clinical data were retrospectively analyzed with the objective of evaluating several potential prognostic factors in thyroid cancer patients eligible for surgical intervention. The primary outcome—days until discharge from hospital—was found to be prolonged in the presence of all four factors tested: age ≥ 45 years, cervical lymph node metastasis, impaired calcium metabolism, and postoperative hypothyroidism.
Japan’s DPC/PDPS provides an incentive for hospitals to systematically discharge patients more quickly. However, none of the four factors examined here are avoidable ones. First, patient age cannot be controlled by the hospital. Second, if already present at admission, complications due to lymph nodes cannot be avoided by any hospital, even by the highest quality of care. Nonetheless, one can still argue for its validity as an indicator of cancer staging in the DPC/PDPS, which assesses fees based in part on disease severity. The incidence of Disorders of calcium metabolism and postoperative hypothyroidism, on the other hand, lack designated payment categories in the CCP matrix; the DPC/PDPS records them separately in the field of secondary diseases, despite the high likelihood of these postoperative complications following thyroid cancer resection.
Disorders of calcium metabolism had the strongest connection with thyroid cancer resection, giving it the highest explanatory power among the factors examined, and is consistent with the findings described by Bilezikian et al. (13) and Suzuki and Takeuchi (12). These conditions develop when the gland is damaged or lost, causing calcium serum levels to drop dramatically and a resulting shortage of thyroid hormone. Symptoms include numbness in the hands and lips, systemic spasms, delirium, and hallucinations; severe cases may go on to develop heart failure or encephalopathy. In addition, thyroid cancer resection is assumed to have a strong association with postoperative hypothyroidism. Loss of the gland leads to a shortage of thyroid hormone, slowing metabolic function throughout the body: psychological symptoms that may be observed include drowsiness, impaired memory, depression, and lethargy. Other symptoms can include dry skin, hair loss, local swelling, and hoarseness due to cellular metabolic disruption, decreased GI motility (constipation), cardiac dysfunction (bradycardia), and general malaise (15, 16). This prognostic factor especially has high explanatory power among patients not treated by surgical intervention, in whom it develops as sudden hypothyroidism.
The exclusion of these conditions from the CCP matrix may reflect a decision by the MHLW that these postoperative complications should not be treated in DPC/PDPS-designated beds, for acute inpatient care. However, Matsuda (2) who had participated in the DPC/PDPS development project describes “length of hospital stay merely indicates one of the indexes of outcome” (p. 142), and “appropriate length of hospital stay should be determined by medical diagnosis and the patient’s intention” (p. 142). The outcome of this study suggests that the incidence of these two conditions after thyroid cancer resection can be interpreted to reveal a mismatch between these patients’ clinical status and bed function as beds covered by DPC/PDPS is for acute inpatient care. The survey data was collected during the period in which DPC/PDPS was first introduced and characterized by “hospital packaged care,” not during the recent era of “regional packaged care,” which has produced great strides in community-based integrated care.
This is likely why patients with these two conditions continued to receive treatment in beds intended for acute inpatient care during this time frame. Nonetheless, these patients should still be receiving care in beds of a lower, sub-acute category, given the ideal of matching patients of a given clinical status with hospital beds of a suitable category based on the stages of political promotion of regional packaged care and functional differentiation of hospitals in Japan (17). Were this possible, developing impaired calcium metabolism or postoperative hypothyroidism after an operation could reduce the average stay of such patients in acute-care beds. Matsuda (1) states that “medical care, long-term care, and prevention of disease should not be affected by regional conditions and accessibility,” (p. 1) and Chikugo (18) states that “one of the barriers of promoting community-based integrated care is shortage of care staff in many areas in Japan” (p. 81).
Patients with impaired calcium metabolism or postoperative hypothyroidism after an operation cannot always be discharged earlier from all hospitals because of staffing issues and the availability of suitable hospital beds. However, the study had some limitations: 1) Inherent limitations and risk of bias due to the study design were present i.e., registry-based and database studies (with retrospective design), 2) the data presented is from 2004 to 2008 and may not be representative of current practices or population characteristics, 3) there might be residual confounding given that the regression models contain only a few variables i.e., not including tumor size, range of thyroidectomy, and stage of cancer, and 4) the results cannot be generalized to other populations (the necessity of re-examining national data). Although there were limitations to this study, four prognostic factors of prolonged hospitalization following surgery for thyroid cancer were identified, namely: age ≥ 45 years, cervical lymph node metastasis, impaired calcium metabolism, and postoperative hypothyroidism. The findings support the conclusion that patients who develop disorders of calcium metabolism or postoperative hypothyroidism after an operation should be transferred to a different bed type or, if possible, to outpatient care. The author hopes that the study findings give readers an opportunity to re-consider optimal acute care strategies in Japan.