2025 Volume 89 Issue 4 Pages 492-499
Background: Heart failure (HF) is growing global issue, especially among older adults, and patients can be hospitalized at any time of day. We compared patients’ characteristics, including precipitating factors leading to HF hospitalization, between daytime and nighttime admissions.
Methods and Results: A total of 1,124 patients, who were primarily admitted with a diagnosis of acute decompensated HF were enrolled. Patients were divided according to time of hospitalization into daytime (n=770; 8 am–6 pm) and nighttime (n=354; 6 pm–8 am) groups. The prevalence of hypertension, new-onset HF, and clinical scenario 1 [systolic blood pressure (BP) at admission ≥140 mmHg], frequency of New York Heart Association class IV symptoms, systolic and diastolic BP, heart rate, estimated glomerular filtration rate (eGFR), serum concentrations of albumin and hemoglobin, and treatment with vasodilators and noninvasive ventilation were greater, while the prevalence of atrial fibrillation, duration of persistent HF symptoms ≥24 h, serum concentration of total bilirubin, loop diuretic use and mineralocorticoid antagonist use before admission were lower in the nighttime group. Among the HF-precipitating factors, nonadherence was the most prevalent in both the daytime (32.2%) and nighttime (29.9%) groups. Poorly controlled hypertension was common in nighttime patients (10.5% vs. 5.1% P<0.001).
Conclusions: Prehospital BP control may contribute to preventing nighttime hospitalizations. Additionally, the most essential step in preventing hospitalizations due to HF, day or night, is patient education and disease management.
Heart failure (HF) is growing global issue, especially among older adults, requiring hospitalization during the day or night. Although some reports have described the features of acute decompensated HF occurring at night, there are differences in the definition of nighttime admission, clinical characteristics, and outcomes.1–5 Additionally, clinical implications based on patients’ characteristics according to the timing of hospital admission are still lacking. We previously showed that the prevalence of malnutrition and systolic blood pressure (SBP) were significantly different between patients admitted during the day and those admitted at night.1 However, it is difficult to describe suggested strategies based on these results.
HF is a heterogeneous clinical syndrome affected by precipitating factors and comorbidities, and a cautious individual approach is required to reduce mortality and HF rehospitalization rates.6,7 Approximately 20 years ago, Tsuchihashi et al. reported precipitating factors leading to readmission in Japan.8 They indicated that patient-related factors, such as nonadherence, were predominant, suggesting that rehospitalizations due to HF exacerbations were, to some extent, preventable. Furthermore, while preventing readmission is important, preventing the initial hospitalization for HF, or even the onset of HF itself, should be a high priority. Thus, we focused on precipitating factors thought to lead to each initial HF hospitalization based on the hypothesis that an observational study that included these values in addition to conventional factors could be more helpful for clinical application.
The objective of this study was to compare precipitating factors leading to hospitalization for HF between daytime and nighttime, and then to consider applicable strategies for preventing HF admission in patients with acute decompensated HF.
In this retrospective study, 1,124 patients who were primarily admitted with a diagnosis of acute decompensated HF to the Cardiology Department of Kasugai Municipal Hospital (from January 2019 to December 2022) were enrolled (Figure 1). Patients on dialysis, or those with acute myocardial infarction,9 and/or cardiogenic shock, and those who experienced worsening HF during hospitalization for other diseases (including surgical procedures and other medical conditions), were excluded, as post-admission noncardiac factors or specialized interventions may substantially affect a patient’s prognosis. For patients with multiple hospitalizations during the study period, the first eligible hospitalization period was evaluated. This study followed the STROBE guidelines, the study protocol complied with the Declaration of Helsinki and it was approved by the Institutional Review Board at Kasugai Municipal Hospital.10 An opt-out informed consent protocol was used. The consent procedure was reviewed and approved by the Institutional Review Board at Kasugai Municipal Hospital.10 None of the participants opted out of the study.
Flowchart of patient enrollment in the study.
Definitions and Data Collection
The clinical characteristics and outcomes were assessed using a chart review. The left ventricular ejection fraction (LVEF) was derived from echocardiographic results using the modified biplane Simpson’s rule on the day of admission, prior to hospitalization or during hospitalization. Patients were divided into 3 groups according to their baseline LVEF: <40%, 40%≤LVEF<50%, and >50%.11 The diagnosis of acute decompensated HF was based on the European Society of Cardiology HF guidelines.11 Both new-onset HF and acute decompensation of chronic HF were included in this study. Resting BP was obtained using an automatic sphygmomanometer applied to the upper arm of the seated patient.12 Based on the SBP at the time of admission, patients were classified as clinical scenario 1 (SBP ≥140 mmHg) or clinical scenario 2 (100≤SBP<140 mmHg). Patients in cardiogenic shock or experiencing acute myocardial infarction were excluded.13 Malnutrition was defined as the Controlling Nutrition (CONUT) score ≥5, calculated using serum albumin concentration, lymphocyte count, and total cholesterol level.14 CONUT score was estimated on day 2 of hospital admission. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation.15 The duration of persistent HF symptoms was defined as the duration from the onset of HF-related symptoms to hospital arrival, and the patient was interviewed by an attending physician at emergency admission. Frailty, defined by the Study of Osteoporotic Fracture Index, was determined based on reports that show this index to be equal to the globally accepted Cardiovascular Health Study Index for assessing frailty.16 Frailty was identified by the presence of ≥2 of 3 components: (1) weight loss (irrespective of intent to lose weight) ≥5% of patient’s own body weight within 2 years; (2) inability to rise from a chair, 5 times, without using the arms; and (3) reduced energy level, as identified by an answer of “no” to the question “Do you feel full of energy?” This index was evaluated within the first 24 h after hospitalization using a simple electronic template. Seasonal variations were evaluated by categorizing hospitalizations as during spring (March–May), summer (June–August), autumn (September–November), and winter (December–February). Patients’ prehospital medical care was classified as regular treatment from primary care physician; regular treatment from the Cardiology Department; or no regular care.
The time of hospital admission was defined as daytime (8 am–6 pm) or nighttime (6 pm–8 am), based on the cutoffs previously reported.1 The day of the week was not considered in this study.
Based on recent observations, precipitating factors were classified as: nonadherence, myocardial ischemia, infections, poorly controlled hypertension, arrhythmias, unknown, other organ disorders, and others (Supplementary Table 1).17–19 Nonadherence included nonadherence to medication, physical activity, and/or diet because of the difficulty in differentiating between them. Poorly controlled hypertension included prehospital BP before worsening HF, not reaching the guideline-recommended target goal or being untreated, or an in-hospital BP ≥140/90 mmHg after initial treatment.12 Arrhythmias included atrial fibrillation, sick sinus syndrome, atrioventricular block, sustained or non-sustained ventricular tachycardia, and atrial tachycardia. One or more precipitating factors nominated by the attending cardiologist at admission were reviewed by other cardiologists at a conference during the index hospitalization.
Statistical AnalysisSAS software (version 27; SAS Institute, Inc. Cary, NC, USA) was used for the statistical analyses. Categorical variables are expressed as counts and percentages, while continuous variables are expressed as median and interquartile range (IQR) or as mean±standard deviation. The distribution of continuous variables was examined using the Shapiro-Wilk test; normally distributed variables were compared using the unpaired Student’s t-test, whereas variables that were not normally distributed were compared using the Mann-Whitney U-test. Univariate and multivariate logistic regression analyses were performed to identify the independent predictors of nighttime admission, and P values, odds ratios (ORs), and 95% confidence intervals (CIs) were calculated. Statistical significance was set at P<0.05. Variables with a P value <0.05 in the univariate analyses were entered into the multivariate model. Multicollinearity was examined using the variance inflation factor prior to the multivariate logistic regression analysis.
The characteristics of the study patients according to the time of admission are shown in Table 1. The median age of the patients was 82 years (IQR: 74–87 years), and 52.0% were male. The prevalence of hypertension, new-onset HF, clinical scenario 1, frequency of New York Heart Association (NYHA) class IV symptoms, systolic and diastolic BPs at admission, heart rate, eGFR, serum concentration of albumin and hemoglobin were greater, whereas the prevalence of atrial fibrillation and duration of persistent HF-related symptoms ≥24 h, serum concentration of total bilirubin, and treatment with loop diuretics and mineralocorticoid antagonist (MRA) before admission, were lower in nighttime patients. There was no significant difference in the proportions of LVEF categories between groups. Among patients with atrial fibrillation, the ratio of those receiving prehospital regular treatment from primary care physicians was significantly higher for daytime admissions (75.3% vs. 24.7%, P<0.001). In the early hospitalization period, vasodilators and noninvasive ventilation were administered more frequently to nighttime patients than to daytime patients (Table 2).
Characteristics of Study Patients According to Time of Hospitalization
| Variable | All patients (n=1,124) |
Daytime admission (n=770) |
Nighttime admission (n=354) |
P value |
|---|---|---|---|---|
| Age (years) | 82 (74–88) | 82 (74–88) | 82 (74–87) | 0.409 |
| Male sex (%) | 52.0 | 50.5 | 55.1 | 0.155 |
| Current or former smoker (%) | 42.8 | 40.5 | 47.7 | 0.062 |
| Body mass index (kg/m2) | 23.0±4.7 | 23.1±4.8 | 22.9±4.3 | 0.955 |
| Living alone (%) | 20.0 | 19.9 | 20.3 | 0.855 |
| Comorbidities (%) | ||||
| Dyslipidemia | 62.9 | 62.7 | 63.3 | 0.859 |
| Type 2 diabetes mellitus | 37.6 | 37.0 | 39.0 | 0.527 |
| Hypertension | 75.0 | 73.3 | 78.8 | 0.045 |
| AF | 41.5 | 45.8 | 31.9 | <0.001 |
| Previous myocardial infarction | 19.8 | 19.0 | 21.5 | 0.353 |
| Previous stroke | 11.8 | 11.4 | 12.5 | 0.617 |
| Chronic obstructive pulmonary disease | 8.2 | 7.5 | 9.6 | 0.239 |
| Frailty | 41.0 | 41.7 | 39.3 | 0.436 |
| Prehospital medical care (%) | <0.001 | |||
| Regular treatment from primary care physicians | 82.6 | 84.0 | 79.7 | |
| Regular treatment from cardiology department | 11.5 | 12.0 | 10.5 | |
| No regular treatment | 5.9 | 4.0 | 9.8 | |
| Previous hospitalization for HF (before the study period, %) | 27.8 | 27.5 | 28.3 | 0.803 |
| New-onset HF (%) | 14.3 | 11.7 | 20.1 | <0.001 |
| Initial evaluation | ||||
| SBP (mmHg) | 148 (126–173) | 139 (122–163) | 169 (143–190) | <0.001 |
| DBP (mmHg) | 87 (70–104) | 82 (68–99) | 98 (81–119) | <0.001 |
| Heart rate (beats/min) | 94 (78–115) | 91 (75–110) | 101 (84–123) | <0.001 |
| Sodium (mEq/L) | 141 (138–143) | 141 (138–143) | 140 (138–143) | 0.898 |
| Potassium (mEq/L) | 4.1 (3.7–4.5) | 4.0 (3.7–4.5) | 4.1 (3.7–4.4) | 0.405 |
| eGFR (mL/min/1.73 m2) | 45.2 (31.1–60.7) | 44.3 (30.1–59.7) | 47.9 (33.5–62.4) | 0.045 |
| Albumin (mg/dL) | 3.4±0.6 | 3.4±0.6 | 3.5±0.5 | 0.006 |
| Total bilirubin (mg/dL) | 0.9±0.6 | 1.0±0.7 | 0.8±0.5 | <0.001 |
| CRP (mg/L) | 6.0 (1.9–19.1) | 5.8 (1.9–19.6) | 6.7 (2.1–18.5) | 0.879 |
| BNP (pg/mL) | 507 (264–910) | 507 (286–929) | 508 (242–894) | 0.298 |
| Hemoglobin (mg/dL) | 11.6±2.4 | 11.5±2.4 | 11.8±2.3 | 0.011 |
| Malnutrition (%) | 50.8 | 52.8 | 46.6 | 0.056 |
| NYHA functional class (%) | <0.001 | |||
| II | 6.2 | 6.4 | 5.6 | 0.690 |
| III | 28.4 | 33.2 | 18.4 | <0.001 |
| IV | 65.4 | 60.4 | 76.0 | <0.001 |
| Clinical scenario 1 (%) | 59.5 | 50.5 | 79.1 | <0.001 |
| LVEFa (%) | 52 (39–65) | 53 (39–65) | 50 (39–65) | 0.590 |
| LVEF category (%) | 0.505 | |||
| <40% | 25.7 | 25.6 | 26.0 | |
| 40%≤EF<50% | 18.5 | 17.7 | 20.3 | |
| EF >50% | 55.8 | 56.7 | 53.7 | |
| Duration of persistent HF symptoms ≥24 h (%) | 39.2 | 44.6 | 27.7 | <0.001 |
| Precipitating factors (%) | ||||
| Nonadherence | 31.5 | 32.2 | 29.9 | 0.448 |
| Myocardial ischemia | 10.1 | 8.8 | 12.7 | 0.054 |
| Infections | 20.9 | 20.2 | 22.6 | 0.350 |
| Poorly controlled hypertension | 6.8 | 5.1 | 10.5 | <0.001 |
| Arrhythmia | 12.7 | 14.0 | 9.9 | 0.053 |
| AF | 8.7 | 9.4 | 7.3 | 0.306 |
| Unknown | 5.3 | 6.1 | 3.4 | 0.062 |
| Other organ disorders | 7.4 | 8.1 | 5.9 | 0.222 |
| Other | 6.3 | 6.5 | 5.9 | 0.793 |
| Medication at admission (%) | ||||
| Loop diuretics | 44.5 | 49.6 | 33.3 | <0.001 |
| Renin-angiotensin system inhibitors | 42.8 | 43.3 | 41.8 | 0.651 |
| β-blockers | 35.3 | 36.4 | 33.1 | 0.280 |
| Mineralocorticoid receptor blockers | 19.1 | 22.1 | 12.7 | <0.001 |
| Sodium-glucose co-transporter-2 inhibitors | 2.9 | 3.1 | 2.5 | 0.705 |
| Calcium-channel blockers | 29.9 | 28.7 | 32.6 | 0.182 |
Data are presented as mean±standard deviation, median (interquartile range), or percentage (%) unless otherwise specified. aKnown on the day of admission, prior to hospitalization, or measured during hospitalization. Malnutrition defined as CONUT score ≥5 in the Controlling Nutrition status values. AF, atrial fibrillation; BNP, B-type natriuretic peptide; CONUT, Controlling Nutrition status; CRP, C-reactive protein; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; HF, heart failure; LVEF, left ventricular ejection fraction; NYHA, New York Heart Association; SBP, systolic blood pressure.
In-Hospital Treatment and Outcomes According to Time of Hospitalization
| Variable | All patients (n=1,124) |
Daytime admission (n=770) |
Nighttime admission (n=354) |
P value |
|---|---|---|---|---|
| In-hospital treatment (%) | ||||
| Intravenous drug therapy | ||||
| Loop diuretics | 92.4 | 91.4 | 94.6 | 0.068 |
| Vasodilators | 39.6 | 29.1 | 62.4 | <0.001 |
| Inotropes | 11.6 | 11.6 | 11.6 | 0.978 |
| Noninvasive ventilation | 12.0 | 7.4 | 22.1 | <0.001 |
| Outcomes | ||||
| Length of stay (days) | 14 (10–20) | 14 (10–21) | 14 (9–20) | 0.161 |
| In-hospital death (%) | 9.1 | 9.4 | 8.5 | 0.630 |
| 1-year all-cause death (%) | 11.8 | 12.6 | 10.2 | 0.242 |
| 1-year post-discharge HF rehospitalization (%) | 15.0 | 14.2 | 16.7 | 0.273 |
Data are presented as median (interquartile range) or percentage (%). HF, heart failure.
Among the precipitating factors, nonadherence was most frequent among both nighttime and daytime patients (29.9% vs. 32.2%, P=0.448), and infections were also common (22.6% vs. 20.2%, P=0.350). Among nighttime patients, poorly controlled hypertension was significantly more common (10.5% vs. 5.1%, P<0.001) (Table 1, Figure 2). Similar rates of in-hospital death, 1-year all-cause death, and 1-year post-discharge HF rehospitalization were observed between groups (Table 2). Of the 76 patients with poorly controlled hypertension as a precipitating factor, 33 were definitively confirmed through either home BP logs or referral documents, 23 were untreated or interrupted, 15 had elevated BP (≥140/90 mmHg) while hospitalized with LV hypertrophy, and 5 had elevated BP (≥140/90 mmHg) while hospitalized without LV hypertrophy. Among patients hospitalized during nighttime, poorly controlled hypertension was almost evenly distributed (Supplementary Figure). Furthermore, there was no relationship between poorly controlled hypertension and body position just before hospital arrival (P=0.159).
Distribution of heart failure precipitating factors according to time of hospitalization.
Next, the HF-precipitated factors were compared between patients admitted during daytime and those admitted in the middle of the night (12 am–3 am). Nonadherence was most frequent in patients admitted in the midnight timeframe (39.0%), as was poorly controlled hypertension (10.4%), though the difference was not significant (P=0.065). Similar rates of in-hospital death, 1-year all-cause death, and 1-year post-discharge HF rehospitalization were observed between groups (data was not shown).
In an analysis according to season, the prevalence of clinical scenario 1, NYHA class IV symptoms, and systolic and diastolic BPs at admission were greater in nighttime patients, whereas the prevalence of duration of persistent HF-related symptoms ≥24 h was lower, across all seasons (Supplementary Table 2). Nonadherence was the abundant factor across all seasons. Among patients admitted during nighttime, poorly controlled hypertension was significantly more common during the summer (11.0% vs. 2.8%, P=0.024) and winter (11.9% vs. 3.0%, P=0.002) seasons (Supplementary Table 2).
Subsequent univariate logistic regression analysis revealed that poorly controlled hypertension was significantly associated with nighttime admission (OR 2.19, 95% CI 1.37–3.50, P=0.001). Although NYHA class IV was significantly associated with nighttime admission in the univariate analysis, NYHA class III or IV symptoms were no longer significant when using NYHA class II symptoms as the reference. SBP at admission, clinical scenario 1, and poorly controlled hypertension as precipitants were not associated with excessive multicollinearity (variance inflation factor <10). Multivariate logistic regression analysis showed that atrial fibrillation, SBP at admission, and heart rate at admission were significantly (P<0.05) associated with nighttime admission (Table 3).
Univariate and Multivariate Logistic Regression Analysis of Factors Related to Nighttime Admission
| Characteristics | Univariate | Multivariate | ||
|---|---|---|---|---|
| OR (95% CI) | P value | OR (95% CI) | P value | |
| Current or former smoker | 1.31 (1.02–1.68) | 0.034 | 1.27 (0.97–1.68) | 0.085 |
| AF | 0.55 (0.42–0.72) | <0.001 | 0.64 (0.48–0.86) | 0.003 |
| No prehospital regular treatment | 2.62 (1.59–4.32) | <0.001 | 1.18 (0.66–2.21) | 0.581 |
| SBP at admission (mmHg) | 1.02 (1.02–1.03) | <0.001 | 1.02 (1.01–1.02) | <0.001 |
| Heart rate (beats/min) | 1.01 (1.01–1.02) | <0.001 | 1.01 (1.00–1.02) | <0.001 |
| Albumin (mg/dL) | 1.37 (1.08–1.73) | 0.009 | 1.13 (0.86–1.48) | 0.390 |
| Hemoglobin (mg/dL) | 1.06 (1.01–1.12) | 0.027 | 0.97 (0.91–1.04) | 0.424 |
| Blood urea nitrogen (mg/dL) | 0.99 (0.98–1.00) | 0.002 | 1.00 (0.99–1.01) | 0.893 |
| Poorly controlled hypertension (as a precipitant) | 2.19 (1.37–3.50) | 0.001 | 1.02 (0.60–1.72) | 0.941 |
| Loop diuretic use at admission | 0.51 (0.39–0.66) | <0.001 | 0.80 (0.59–1.10) | 0.169 |
| MRA use at admission | 0.51 (0.36–0.73) | <0.001 | 0.85 (0.57–1.27) | 0.430 |
Multivariate logistic regression analysis was performed with variables identified in univariate analyses, including current or former smoker (0, no; 1, yes), AF (0, no; 1, yes), no prehospital regular treatment (0, no; 1, yes), SBP at admission (mmHg), heart rate (beats per minute), albumin (mg/dL), hemoglobin (mg/dL), blood urea nitrogen (mg/dL), NYHA functional class IV (0, no; 1, yes), poorly controlled hypertension (0, no; 1, yes), loop diuretic use at admission (0, no; 1, yes), and mineralocorticoid receptor agonist (MRA) at admission (0, no; 1, yes). CI, confidence interval; OR, odds ratio. Other abbreviations as in Table 1.
A major strength of this study was its inclusiveness; identifying precipitating factors leading to HF hospitalization showed promise for raising plausible challenges for the treatment of HF according to the timing of patients’ hospitalization. To the best of our knowledge, this is the first study to investigate the HF-precipitating factors according to the timing of hospitalizations. We showed that nonadherence was the most common precipitating factor for admission at any time, and across all seasons, and those who had poorly controlled hypertension were most commonly admitted at night. These results highlight the necessity for efforts directed toward adequate education and management before hospitalization, including BP control, strategies that can be applied by all clinicians and in all settings.
Studies have reported different characteristics of patients with HF according to the time of presentation. The present analysis was consistent with our previous report1 and the observations of others2,5 of elevated BP, high heart rate, and high frequency of NYHA functional class IV symptoms. We also identified high concentrations of albumin and hemoglobin, low concentrations of total bilirubin, and infrequent treatment with loop diuretics and MRA before admission, suggesting that nighttime patients may worsen more rapidly with less excessive fluid retention than daytime patients. Additionally, the prevalence of atrial fibrillation was lower among nighttime patients, suggesting that nighttime patients present with a more rapid onset, which aligns with the finding of a previous report.4 The result that fewer patients with persistent HF symptoms ≥24 h were admitted during nighttime strengthens this consideration. Matsushita et al.2 reported that the administration of nitroglycerin and noninvasive ventilation occurred significantly more often for nighttime patients, and that this treatment strategy was optimal. The fact that the administration of vasodilators and noninvasive ventilation during hospitalization was greatly needed supports this recommendation. However, the shorter length of stay during the nighttime in our previous study was not replicated in the present study. This finding requires further analysis in other populations with multiple-participant panels. The results from the REPORT-HF registry suggest that economic factors influence time-based variation in HF admission, such as the presence of families and primary care providers who can take a patient to hospital.3 Our finding that a higher ratio of patients admitted during daytime received regular prehospital treatment from a primary care physician was consistent with that report.
Most patients with HF present with a subacute presentation of worsening signs and symptoms over the course of days to weeks. Therefore, it is possible to manage specific treatments and prevent hospitalization due to HF even after worsening at the outpatient clinic.20 In contrast, patients with arrhythmias, ischemia, or extreme hypertension may show rapid deterioration within a day. It may be difficult to interrupt the clinical course toward HF exacerbation after worsening. However, adequate BP control in routine outpatient clinics before HF worsening could prevent exacerbation. Our results that nighttime patients had not only elevated BP at emergency admission and increased prevalence of hypertension, but also frequently had poorly controlled hypertension support this speculation. To date, large randomized controlled trials have indicated that targeting an intensive reduction in SBP is a beneficial strategy for preventing the occurrence of HF,21–23 and could be responsible for the decreased incidence of hospitalizations due to HF in clinical practice. Nevertheless, differences in the awareness of and willingness for hypertension control among HF patients has been reported between hospital cardiologists and general physicians.24 Despite this, BP control before HF worsening could lead to a reduction in nighttime admissions of HF patients. Acute decompensated HF is reportedly due to a fluid shift with increasing venous return, decreased responsiveness of the respiratory center in the brain, and decreased adrenergic activity in the myocardium during sleep.25 Clinical reports show that a morning surge and nocturnal hypertension, which includes the riser BP pattern, are important triggers for the development of HF.26–28 Our finding of no particular trend in the HF-precipitating factors among patients admitted in the midnight timeframe differs from those previous reports. Postural effects just prior to hospital arrival on poorly controlled hypertension were also not observed. However, given that nighttime frame in this study included early in the morning, it is possible that nocturnal to early morning elevations in BP could affect HF exacerbations during the nighttime. Further studies with accurate BP data obtained overnight and the exact timing of HF exacerbation (not the timing of hospitalization) are needed to clarify this association.
Hirai et al. reported that among patients with HF, clinical scenario 1 was significantly more frequent during the winter.29 Due to seasonal variations of HF, patients admitted during nighttime in winter may show distinct characteristics, including precipitating factors, but our findings were not in line with that hypothesis. This discrepancy may be attributed to other patient and regional characteristics that were not investigated in the present study.
Although poorly controlled hypertension was a significant precipitating factor for nighttime admissions, nonadherence was the most dominant factor irrespective of the time of hospital admission. Tsuchihashi et al. reported a similar trend,8 suggesting that this has been a challenge for the management of patients with HF for over 20 years. In their study, common factors thought to precipitate hospitalizations for HF included nonadherence to diet (33%) and infections (20%).8 Given that nonadherence is often associated with a lack of knowledge about adequate dietary patterns, including salt and water, physical activities, or the necessity of prescribed medications, greater dissemination of patient-centered education by multidisciplinary staff should be effective in reducing hospitalization rates.20 Therefore, the guidelines strongly recommend individual patient education by professionally trained staff members, with special emphasis on self-care and symptom management.11 A recent observational study showed that intensive multidisciplinary education with nurses, pharmacists, and nutritionists improved the outcomes of Japanese patients with HF.30 In the present study, most patients received regular prehospital treatment, either from a primary care physician or the Cardiology Department, suggesting that they were receiving multidisciplinary intervention and HF education. However, the fact that some patients were referred at their first visit to a primary care physician makes it difficult to establish the presence or absence of prehospital education. Regardless, we believe that our findings, which indicate prehospital education is the most effective method in preventing HF hospitalizations, both daytime and nighttime, are easily applicable to clinical practice in our region.
Study LimitationsFirst, the results presented here are only from a single hospital and were not replicated in other hospitals. Second, some HF-precipitating factors may have only been identified by interview or just a prediction. Third, in many patients with poorly controlled hypertension, detailed prehospital BP data was not collected. Fourth, paroxysmal and persistent atrial fibrillation could not be classified.
In summary, adequate prehospital BP control may contribute to the prevention of HF hospitalization, especially for patients admitted during nighttime. In addition, the most essential step in preventing HF hospitalizations, both daytime and nighttime, is patient education and disease management.
We gratefully acknowledge the work of present members of our department for their helpful discussions and comments on this manuscript.
T.M., T.A., and H.I. are members of Circulation Journal’s Editorial Team. Other authors declare no conflicts of interest.
The study protocol was reviewed and approved by the Institutional Review Board at Kasugai Municipal Hospital (No. 355).
The deidentified participant data will be shared on request to the corresponding author. All data will be shared, as will the study protocol. Data will be available from within 6 months after publication for a period of 1 year. Data will be shared after permission has been granted by the Committees on Ethics of Kasugai Municipal Hospital. For any kind of analyses, the data will be shared as Excel files via email.
Please find supplementary file(s);
https://doi.org/10.1253/circj.CJ-24-0653
