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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 17  |  Issue : 1  |  Page : 42-47

Short-term outcomes and their predictors among patients admitted with acute heart failure in a Nigerian Teaching Hospital


1 Department of Internal Medicine, General Amadi Specialist Hospital, Katsina, Nigeria
2 Department of Medicine, Bayero University Kano and Aminu Kano Teaching Hospital, Kano, Nigeria
3 Department of Medicine, Jos University Teaching Hospital, Jos, Plateau State, Nigeria

Date of Submission12-Sep-2019
Date of Decision10-Mar-2020
Date of Acceptance30-Mar-2020
Date of Web Publication30-Jun-2020

Correspondence Address:
Dr. Muhammad Nazir Shehu
Department of Internal Medicine, General Amadi Specialist Hospital, Katsina
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njc.njc_20_19

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  Abstract 


Background: Despite many recent advances in the evaluation and management of heart failure (HF), the development of symptomatic HF still carries a poor prognosis. A study of clinical characteristics of patients with acute heart failure (AHF) will provide appropriate clinical decisions with regard to treatment and patients' monitoring. This study therefore aimed to determine the clinical characteristics of patients admitted with AHF. The outcome measures are death, rehospitalization, or combined death/rehospitalization.
Methods: It was a longitudinal study carried out on eligible AHF patients aged 18 years and above who were consecutively recruited. On presentation, all patients had history obtained and physical examination performed. Baseline blood chemistry, full blood count, electrocardiography, and echocardiography were carried out as well. Data on vital status and rehospitalization/death were recorded at 1 month, 3 months, and 6 months of follow-up periods.
Results: A total of 120 patients were studied. Fifty-five percent of them were female, and the mean age was 49.88 ± 18.87 years. Of the 120 patients studied, 35 (29.2%) died, 21 (17.5%) were rehospitalized only once, and 2 (1.7%) were rehospitalized twice. Renal impairment (RI) was an independent predictor of both mortality from AHF (odds ratio [OR] = 2.875, 95% confidence interval [CI]: 1.207–6.874 and P = 0.012) and composite endpoint of death or rehospitalization (OR = 3.131, 95% CI: 1.326–7.890, and P = 0.009). Rehospitalization was significantly higher among diabetics (OR = 5.000, 95% CI: 1.604–15.586 and P = 0.006).
Conclusion: AHF was associated with high mortality rate and composite endpoint of death or rehospitalization. RI and diabetes were the independent predictors of poor outcomes.

Keywords: Acute heart failure, Kano, outcomes


How to cite this article:
Shehu MN, Sani MU, Okeahialam BN. Short-term outcomes and their predictors among patients admitted with acute heart failure in a Nigerian Teaching Hospital. Nig J Cardiol 2020;17:42-7

How to cite this URL:
Shehu MN, Sani MU, Okeahialam BN. Short-term outcomes and their predictors among patients admitted with acute heart failure in a Nigerian Teaching Hospital. Nig J Cardiol [serial online] 2020 [cited 2020 Aug 12];17:42-7. Available from: http://www.nigjcardiol.org/text.asp?2020/17/1/42/288644




  Introduction Top


Acute heart failure (AHF) is defined as a rapid or gradual onset of the symptoms and signs of heart failure (HF), resulting in the need for urgent unplanned hospitalization or office or emergency department visits.[1] It represents a significant public health burden, resulting in millions of hospitalization and increased cost of health care worldwide.[2] Community-based studies indicate that 30%–40% of patients die within 1 year of diagnosis and 60%–70% die within 5 years mainly from worsening HF or as a sudden event (e.g., ventricular arrhythmia).[3],[4] HF is therefore fatal and has a greater impact on quality of life as compared with other chronic illnesses such as arthritis, diabetes mellitus, and hypertension.[3]

The heterogeneous nature of AHF patients suggests that this variation in patient characteristics may play a role in their outcome. Accordingly, it is important to understand current characteristics and modern clinical care concepts of patients hospitalized with AHF.

This study sought to determine the clinical characteristics of AHF among patients admitted in Aminu Kano Teaching Hospital (AKTH), specifically looking at the short-term outcomes and their predictors in AHF. The findings obtained could at least serve as baseline data on which larger initiatives exploring both pathophysiology and treatment of AHF could be built upon in the future.


  Methods Top


The study was conducted at AKTH, Kano, North Western geopolitical zone of Nigeria.

The study was a longitudinal, and the study population was made up patients hospitalized with AHF. The inclusion criteria were (1) patients 18 years and above, (2) having a primary diagnosis of AHF, and (3) consented to be part of the study.

Minimum sample size was calculated using the formula – N = Z2 PQ/d2[5] applying the precision of 5% and prevalence of AHF of 7%. The prevalence was obtained as an average of a local study on HF (10%) and AHF study (4%).[2],[6]

N = Z2 PQ/d2 where

N = Minimum sample size

Z = Constant at 95% confidence interval (CI) (i.e., 1.96)

P = Best estimate of prevalence of HF literature expressed as a fraction of 100 (in this case 7%=0.07).

Q = (alternative probability) 1.0 − P (0.93)

d = absolute precision limit required (5%) 0.05

Thus, N = (1.96) 2 (0.07) 0.93/(0.05) 2 = 100

However, 120 patients were recruited for this study to cover for possible defaults and to aim for a higher statistical significance. Patients who satisfied the inclusion criteria were recruited consecutively until the required sample size was achieved.

Patients who were suspected to have AHF at the emergency unit or cardiac clinic of the AKTH were screened and subsequently sent to the medical wards. Each consenting patient who satisfied the inclusion criteria for the study was interviewed using a standard pro forma to obtain demographic data, clinical history, and general and cardiovascular examinations. The patients' addresses and phone numbers were collected on admission.

HF was diagnosed according to the Framingham criteria.[5] This consists of the major and minor criteria for HF. Serum urea, electrolytes and creatinine (Cr), complete blood count, serum albumin, and lipid profile were carried out on all patients. Twelve-lead surface electrocardiogram (ECG) was recorded for all qualified patients in the ECG laboratory of AKTH using Schiller ECG machine by the investigator in the standard fashion. All recordings were done 5–8 h postprandial with styli control set at 10 mm/mV and paper speed at 25 mm/s. Five cardiac cycles were recorded per lead and a long lead II taken to serve as rhythm strip.

Transthoracic echocardiography was performed in all patients using ALOKA SSD-4000 machine. Patients were examined in the left lateral decubitus position using standard parasternal, short-axis, and apical views. The left ventricular (LV) measurements taken included interventricular septal thickness in end diastole, posterior wall thickness in end diastole, LV internal diameter (LVID) in end diastole, and LVID in end systole. LV systolic function was calculated by Teichholz's formula.[7] All measurements were done according to the recommendation of the American Society of Echocardiography methods of leading-edge to leading-edge convention.[7] Continuous-wave Doppler was used to interrogate the valves when there was suspicion of any valvular lesion, whereas tissue Doppler imaging was used to differentiate normal from pseudonormal LV filling.

The total period of the study was 11 months, consisting of 5 and 6 month's recruitment and follow-up periods, respectively. At discharge and follow-up, symptoms of HF, as well as hospital readmission/death, were assessed and recorded. Follow-up was at 1 month, 3 months, and 6 months. Those patients who were not present at the appointed time for follow-up had a phone call to collect data on symptoms of HF and rehospitalization/death.

All data generated were collated, checked, and analyzed using computer-based Statistical Package for the Social Sciences version 16.0 (IBM Co-operation, Armonk, New York, U.S.A.). Quantitative variables were described using mean and standard deviation. Qualitative variables were presented as percentages and bar chart. The nonparametric test (Chi-squared) or Fisher's exact test was used to test for significance among categorical variables. Multivariate analysis, using binary logistic regression model, was used to determine predictors of short-term outcomes. CI of 95% was used and P < 0.05 was used for significance.

The Ethical Committee of AKTH approved the protocol for the study and informed consent was obtained from each patient. The provisions of the Helsinki declaration were respected.[8]


  Results Top


A total of 120 patients who satisfied the inclusion criteria were studied over a period of 11 months. Paroxysmal nocturnal dyspnea, cardiomegaly, third heart sound, and pulmonary rales were the most common clinical findings among the patients [Table 1]. History of significant cigarette smoking was found among 6 (5%) patients and all of them were male.
Table 1: Sex distribution of clinical characteristics of patients

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Hypertension was present in 68 (56.7%) patients and was the cause of AHF in 53 (44.2%) patients [Table 2]. Fifteen of the patients who were hypertensive had their AHF attributed to dilated cardiomyopathy, acute myocardial infarction (AMI), cor pulmonale, and PPCM in 7, 5, 2, and 1 patients, respectively, and so hypertension was classified as a comorbid condition in them [Table 3]. Renal impairment (RI) was significantly higher among males [Table 3]. Sixteen patients were diabetics, out of which 14 had concomitant hypertension and diabetes with their AHF attributed to hypertensive heart disease. This comorbid hypertension and diabetes were significantly higher among males [Table 3].
Table 2: Sex distribution of etiologies of acute heart failure

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Table 3: Sex distribution of comorbid conditions of the study population

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LV hypertrophy was the most frequent ECG finding recorded in 89 (74.2%) patients [Table 4]. Arrhythmias were found in 71 (59.2%) patients; 66 (55%) of these were supraventricular. Other arrhythmias found were ventricular tachycardia and bradycardia. These were detected in 5 (4.2%) patients.
Table 4: Electrocardiographic findings of the patients

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[Table 5]a shows echocardiographic parameters according to the type of AHF (systolic vs. diastolic). The group with diastolic dysfunction differed significantly from the two other groups (systolic dysfunction and those with both dysfunctions), in measures of LV geometry. The group with systolic dysfunction is comparable with that of both systolic and diastolic dysfunction groups, apart from ejection and shortening fractions which are significantly lower in the group with both systolic and diastolic dysfunctions. No significant difference was found in the measures of transmitral valve flow among all the three groups.


Click here to view


[Table 5]b shows the echocardiographic features according to primary underlying etiology. The mean LV ejection fraction (LVEF) for all patients was low (37%). The patients with AMI had preserved chamber dimensions and LVEF. Patients with rheumatic valvular heart disease (RVHD) had the largest mean left atrial dimension, but had preserved LVEF despite large LV as well (LV volume overload pattern).

Of the 120 patients studied, 35 (29.2%) died, 21 (17.5%) were rehospitalized only once, and 2 (1.7%) were rehospitalized twice. Among those who died, 18 (51.4%) were male and 17 (48.6%) were female. The difference was not statistically significant (P = 0.364). Of the 35 deaths that occurred, 21 (60%) occurred during the first 3 months of AHF. Twelve (57.1%) females and 9 (42.9%) males were rehospitalized once for AHF (P = 0.828). Overall, 24 (47.1%) males and 27 females (52.9%) had an outcome (death or rehospitalization). All the two patients rehospitalized twice were female.

[Table 6] shows the prognostic factors of AHF. Univariate analysis showed that 6-month mortality rate was statistically significantly higher among patients with RI (P = 0.015). Only diabetic patients had statistically significantly higher rate of rehospitalization in univariate analysis compared with nondiabetics (P = 0.003). The composite endpoint of death or rehospitalization for AHF was statistically significantly higher among patients with RI (P = 0.008). Both 6-month mortality and composite endpoint of death or rehospitalization were significantly higher in the first 3 months of AHF (P = 0.001).
Table 6: Prognostic factors of acute heart failure

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After binary logistic regression analysis, RI and diabetes were found to be the predictors of short-term outcomes (death or rehospitalization for AHF) among patients admitted with AHF in this study.

RI was associated with mortality from AHF (OR = 2.875, 95% CI: 1.207–6.874 and P = 0.012) and composite endpoint of death or rehospitalization (OR = 3.131, 95% CI: 1.326–7.890, and P = 0.009). Diabetics were significantly at higher risk of rehospitalization than nondiabetics (OR = 5.000, 95% CI: 1.604–15.586 and P = 0.006).


  Discussion Top


In this study, we describe the short-term outcomes and their predictors in patients admitted with AHF.

The patients in this study were relatively young with a mean age of 49.88 ± 18.87 years. The finding is similar to earlier study done 4 years ago at AKTH, and a study at University of Ilorin Teaching Hospital Nigeria, where they found mean ages of 46.9 ± 17.89 and 53.3 ± 11.5 years, respectively.[6],[9] The study finding is, however, in contrast to what was reported from the United States of America (61 ± 18 years) and Europe (71.3 ± 12.7 years).[10] The age difference may be in part due to earlier occurrence of some of the causes of HF common in our patients. For instance, peripartum cardiomyopathy (PPCM) and RVHD are known to occur in relatively younger patients.[6],[11],[12],[13] The preponderance of females in this study agrees with earlier studies done in Nigeria.[13],[14] It however disagrees with the findings of other studies which revealed male preponderance.[6],[15],[16] The latter studies have highlighted small sample size (66, 79, and 82, respectively) as their most important limitation which might explain the disparity. In addition, PPCM, which is a common disorder in the environment of this study, was the third most common etiology of AHF in this study and is exclusively a female disease.

High mortality rate and high rate of composite endpoint of death or rehospitalization have been recorded in this study among diabetics and patients with renal dysfunction. Similar mortality rate of 29% was recorded in a multicenter study of determinants of prognosis among Africans with hypertensive HF done in Ilorin North-Central Nigeria and Gambia.[9] In a study done at Sagamu South-western Nigeria on advanced HF, the total mortality over the 36-month study period was 67.1%.[16] The higher mortality rate in the Sagamu's study may not be unconnected to the higher morbid patients, specifically recruited in the study. In a community cohort study, the 6-month postdischarge risk of death, was 26%.[17]

Among the deceased, 51.4% were male and 48.6% were female. Although the difference was not statistically significant, the finding supports the widely reported higher mortality in men with HF compared with women.[6],[16],[18]

It has been reported that about 45% of patients hospitalized with AHF would be rehospitalized at least once (and 15% at least twice) within 12 months.[19],[20] The lower rate of rehospitalization recorded in our study may not be unconnected with the lack of awareness and financial constraints to come for rehospitalization by the patients with decompensation. Financial constraints play a significant role in this circumstance as patients mostly pay out of pocket for health care in Nigeria. Female preponderance in rehospitalization and composite endpoint of death/rehospitalization were recorded. Female gender incurred a two times greater risk of HF rehospitalization within a short time after hospitalization for HF (median 52 days), as reported in a study on effect of gender on rehospitalization in patients with HF.[10]

We found that RI, diabetes, and first 3 months of AHF were associated with poor outcomes. RI is common among patients with HF, and previous studies have demonstrated that approximately 20%–40% of patients admitted to a hospital for AHF have co morbid RI, based on clinical history and serum Cr levels.[21] Comorbid RI in HF is increasingly recognized as an independent risk factor for morbidity and mortality.[22]

Diabetes may have a deleterious impact on the natural course of HF particularly in those with ischemic cardiomyopathy. Diabetes and ischemic heart disease may interact to accelerate the deterioration of myocardial dysfunction, HF progression, and unfavorably influence prognosis.[23],[24]

The study is limited by short follow-up period as well as lack of facilities/high cost of assessing serum level of brain natriuretic peptide (BNP)/NT pro BNP.


  Conclusion Top


AHF was associated with high mortality rate, modest rehospitalization rate, and a high composite endpoint of death or rehospitalization. RI and diabetes were identified as the independent predictors of the short-term outcomes in patients admitted in AHF. Early diagnosis and prompt treatment of RI and diabetes should be emphasized to reduce the short-term outcomes in patients with AHF.

Acknowledgments

We highly appreciate the efforts and support of the head of Department of Medicine, Aminu Kano Teaching Hospital Kano in the person of Prof. MM Borodo and the entire staff of the department toward the successful completion of this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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