In this study, we revealed risk factors for preventing unplanned hospital readmission after discharge of PMV patients receiving home care. This study mainly aimed to explore the relative risk factors in the pre-discharge period during previous hospitalization to prevent the unplanned hospital readmission of these patients. PImax, the hemoglobin level, and a history of cardiovascular disease were the main risk factors that can lead to readmission less than 30 days after discharge. The results are significant because these imply that HMV patients' chances of avoiding readmission after discharge depend on their recovery levels, mainly their respiratory muscle strength and oxygen delivery ability, during the pre-discharge period. Clinical care can use the findings of this study for reference.
The prevalence of unplanned hospital readmissions among HMV patients has attracted limited research attention. Although the present study is not a prospective or a cohort-design study, it comprehensively expressed the percentage of unplanned readmissions every year in the subsequent five years. A significant finding of this study for improving the quality of clinical care is that the percentage of early readmission in the ≤ 30 days interval after discharge was very high; it was the highest in the 31–180 days interval, and even in the 30 days group, the average interval was 15 days. Thus, this finding clarifies the timing of readmission risk among HMV patients receiving home care. Lindenauer et al analyzed data on 226,545 patients in 4,675 hospitals in the United States, who were aged more than 65 years and were hospitalized owing to a diagnosis of pneumonia 18. The 30-day readmission rate was 17.4%, and among these patients, 55.5% were females. In addition, Douglas et al conducted a larger prospective longitudinal descriptive study to identify the risk factors for readmission for 199 patients in the intensive care unit with a history of long-term use of ventilators 19. They found that the readmission rate was 21.1% at 30 days after hospital discharge, which increased to 34.2% at 60 days after discharge. For the 1 to 60 days interval, the average number of days of hospitalization on readmission was 39.2 days and the median was 19 days; however, the hospital readmission rate for the 180-day interval was 8%. In addition, 38.2% of the patients were readmitted at least once, and 14.6% had been hospitalized 2–7 times. Therefore, the results of the present study are similar to those of Douglas’s study, which showed a very high readmission during the 1 to 60 days after discharge among patients with a long-term use of ventilators.
Further, we explored the risk factors for the unplanned hospital readmission of HMV patients. Our study explored the readmission factors that focused on pre-discharge about hospitalization parameters of recovery status during previous hospitalization in HMV patients. Graham et al have analyzed numerous types of data on patients’ admission in the United States 20. Their prospective cohort study analyzed data from 10 academic medical centers with a total of 822 general ward patients in order to determine the risk factors of readmission after discharge for preventing readmission. Their results showed risk factors; there were 301 (36.6%) early readmissions and 521 (63.4%) late readmissions. The mean ages for the early and late readmission groups were 54.7 and 55.5 years, respectively. As regards these patients’ history of chronic diseases, patients with heart failure function grade III or IV accounted for 15.0% and 12.9% of the total readmissions. The authors also pointed out that 36.2% of early readmissions and 23% of late readmissions can be prevented. The risk factor of history of cardiovascular disease was significantly manifested in patients who were readmitted in an earlier time interval, which is a finding similar to that of the present study. In addition, a prospective study of 297 patients older than 60 years by Sharma and other scholars explored whether the nutritional status of elderly patients at admission predicts early or late unplanned readmission or death after discharge 17. The average age was 80.3 years, 64.3% of these patients were females, and the average number of comorbidities was 6.2. The average Charlson Comorbidity Index was 2.3 points. In the diagnosis of diseases, respiratory diseases, sepsis, and cardiovascular diseases were the three main diagnoses. It is specifically demonstrated that the malnutrition of elderly patients upon admission is an important predictor of early readmission or death after hospital discharge. However, the exploratory strategy we adopted in this study allowed us to use hospitalization data as a risk factor, and to consider whether the risk factor of readmission is associated with hospitalization parameters at pre-discharge. Our study differs from other studies in that we focused on HMV patients.
To identify the risk factors of unplanned hospital readmission in the present study, we analyzed the previous hospitalization data about demographics, laboratory data, and clinical and respiratory parameters at pre-discharge in HMV patients. A comparison of early and late readmission showed that significant risk factors were patients' weight, BMI, history of hypertension and cardiovascular disease, the comorbidity index for history of disease, the lack of a caregiver, and a diagnosis of pulmonary and infectious diseases. The risk factors associated with mechanical ventilation were the rate of oxygen use, PImax, PEmax, and RSBI for the weaning profiles. Analysis of clinical laboratory data showed that the significant risk factors were the white blood count, and the levels of hemoglobin, potassium, and magnesium. The significant risk factors were worse for the early readmission group than for the late readmission group. In a survey in the United States by Scheinhorn et al, the average age of PMV patients was 71.4 years 5. The average age of PMV patients in Italy, as Polverino’s study reported, was more than 70 years 21. In the meta-analysis study of Rodakowski and colleagues 22, the demographic characteristics of caregivers showed that their age varied greatly; further, 34% of caregivers were men, of which 61% are spouses or partners and 35% are their adult children. In the elderly patient discharge plan, the impact of using the integrated discharge plan was compared with the normal discharge plan. After the implementation of the integrated discharge plan, the elderly patients’ 90-day readmission reduced by 25%, and 180 days after the implementation of the integrated discharge plan, hospital admissions decreased by 24%. A study by British scholars, such as Lone et al, also showed that pneumonia, chronic obstructive pulmonary disease, sepsis, and decompensated congestive heart failure were the most common causes of respiratory failure in patients requiring PMV 4. Prescott et al conducted a systematic review of studies from the United States, Spain, Canada, Croatia, and Sweden on the readmission of patients with pneumonia after discharge 13. The most common readmission diagnoses are pneumonia, heart failure and cardiovascular disease, chronic obstructive pulmonary disease and lung disease, and sepsis, despite subjects without HMV, which is similar to the results of our study. The present study showed that for hemoglobin ≥ 10.1 g/dL compared with < 10.1 g/dL, the risk ratio of readmission within 30 days significantly reduced by 0.280 times. Similarly, it is predicted that the increased unplanned readmissions within 30 days for every unit of hemoglobin reduction among general medical inpatients will increase the readmission rate by nearly 4% 23. In addition, the present study found that the risk of readmission within 30 days on setting the oxygen flow rate of the home ventilator at ≥ 3L/min was 4.151 times higher than the risk on setting this rate at < 3L/min. A comparison of PImax < − 30 cmH2O and ≥ − 30 cmH2O showed that the risk ratio of readmission within 30 days was reduced to 0.207 times in the latter case. Supinski et al analyzed data on adult patients in the Intensive Care Unit of the University of Kentucky Department of Internal Medicine who used ventilators. They found that the patient's PImax measurements were statistically significant and affected the patients' ventilator use time and survival 24. Hamazaki et al studied 456 patients in Japan with congestive heart failure who received cardiac rehabilitation for 5 months during hospitalization and after discharge 25. They revealed that the higher the PImax was, the higher was the survival rate and that it was even an independent predictor of patient readmission and mortality. Mikkelsen et al reported that improvement in exercise capacity during a cardiac rehabilitation program was highly predictive of the future risk of readmissions for cardiovascular disease and mortality 26. Thus, the results of these studies are all similar to our results, which indicate that hemoglobin, circulation, and respiratory muscle strength affect oxygen delivery to cover oxygen consumption during exercise capacity, and thus, help patients to avoid readmission. Therefore, if patients can cope with the daily activity at home, which is dependent on the level of cardiopulmonary function recovery and endurance at pre-discharge, they can avoid hospital readmission. Conversely, the consequence of inefficient coping by HMV patients may be unplanned hospital readmissions.