Role of BAP 65 (Blood Urea Nitrogen, Altered Mental Status, Pulse, Age 65 Years) Scoring System in Risk Stratification of Patients with Acute Exacerbation of Chronic Obstructive Lung Disease in Tertiary Care Hospital

Introduction: Exacerbations are important events in the management of COPD because they negatively impact health status, rates of hospitalization and readmission, and disease progression. COPD AE is one of the commonest case presenting to the TUTH Emergency, average being 5 patients a day. The aim of the study was to co-relate the BAP 65 score, mortality and mechanical ventilation in patients with acute exacerbation of COPD. Methods: It was an observational study, 648 patients from emergency of TUTH were screened for the study from Magh 2073 to Asar 2074 after getting approval from the institutional review boards, among them 114 were included after applying inclusion and exclusion criteria and BAP 65 score was calculated. The patients were followed till discharge, mechanical ventilation or mortality. Data entry was done in MS EXCEL and statistical analysis was done using SPSS version 24. Results: Total of 114 patients enrolled for the study from the emergency of TUTH. There were total 16 mortality and 12 patients were mechanically ventilated. Most of the mortality and mechanical ventilation were from severe group ie BAP class IV and V. We used Pearson Chi-squared test to compare between BAP 65 class and Mortality, and found that mortality rate increased with increasing BAP 65 class with a p value of < 0.0001. The need of Mechanical Ventilation increased as well, as the BAP 65 Class increased, less than 1% of the patients with BAP class I needed MV, the cause being Type II Respiratory Failure, while around 50% of the patients with BAP class V needed MV (based Pearson Chi-squared test, with a p value of < 0.0001). Conclusions: BAP 65 score is an effective and simple tool to classify the patients presenting with AECOPD, it correlated well with both the need of mechanical ventilation and mortality. Higher the score higher the chances of severe disease.


INTRODUCTION
COPD exacerbations are complex events usually associated with increased airway inflammation, increased mucus production and marked gas trapping. Depending upon the severity of an exacerbation and/or the severity of the underlying disease, an exacerbation can be managed in either the outpatient or inpatient setting. 1 Recently, few clinical scores have been developed to assess the severity of AECOPD aiming to help clinicians in their decisions regarding patients suffering such episodes, the most important being DECAF score, modified DECAF score, 2008 score, BAP 65 score, but none of them is yet widely accepted or recommended to be used in practice. BAP 65 ( Elevated BUN, Altered Mental Status, Pulse and Age > 65 ) is a new model that was developed to predict mortality and need for mechanical ventilation during hospitalization of patients with AECOPD, because it is simple and rapid score, that is designed to only use variables that are generally available to physicians at the time of presentation. 2 The main aim of the study is to generate the role of BAP 65 scoring system in risk stratification of patients with AECOPD.

METHODS
A prospective cross-sectional study was conducted in Teaching Hospital, Kathmandu Nepal.
Teaching Hospital Emergency, Observation, Medical Wards, Medical ICU, ICCU and ICU were selected as the study area. Data collection was done from Magh 2073 to Asar 2074, total of 6 months duration.

Sample size calculation
It was calculated using following formula n = Z 2 pq/d 2 where, n is the sample size Z is confidence interval, for 95% confidence interval Z is 1.96 p is the prevalence of COPD in percentage q is (100-p) d is the desired precision (with margin of error of 4%) Hence, sample size = (1.96) 2 × 5 × (100-5)/4 2 = 114 So, the necessary sample size was 114 Non probability purposive sampling method was used for the study. All the patients admitted with the primary diagnosis of COPD were assessed for the inclusion exclusion criteria during the sample collection period.

Case
Subjects were defined as the case of AECOPD on the basis of their history-clinical GOLD criteria (dyspnea, chronic cough, chronic sputum production, history of exposure to risk factors, family history of COPD) physical examination, chest x-ray and blood investigations.
Subjects with prior diagnosis of COPD by respiratory physician (with typical presentation, risk factors and exclusion of other lung pathology like Pulmonary Tuberculosis, Post TB fibrosis/bronchiectasis, Interstitial Lung Disease, Bronchogenic Carcinoma) under domiciliary oxygen were also taken as advanced COPD cases.

Inclusion criteria
The patients 40 years or older with the diagnosis of AECOPD presenting to the ED of TUTH during data collection period. As the patient presented in emergency, initial assessment of patient was done after carefully applying the inclusion-exclusion criteria, those who met the inclusion criteria were then enrolled. History was taken and physical examination was done after informed consent. Performa was filled. Age, Sex, presenting symptom, major risk factor, smoking habit and smoking status were taken as the baseline characteristics in cases. Data about the discharge from ER, admission in observation, general ward, monitoring bed, need of intubation, mortality and duration of hospital stay were recorded.
Data were taken from the emergency ticket, lab report sheet and patients were followed till discharge or death in hospital. Statistical package for social sciences (SPSS) software version 24 was used to analyze the data. Both descriptive and inferential statistics were used for analysis. In descriptive statistics; frequencies, mean and standard deviation were computed. In inferential statistics, Chi-squared test was performed to establish the significance between the variables and Pearson correlation test were applied to test the association and significant differences in proportion between categorical variables. To analyze the predictive ability of BAP 65 score for the primary end point ROC curve was used. All the statistical analysis were 2 tailed and p value of < 0.05 was considered to be statistically significant.
Study was conducted after getting approval from the IRB. Verbal and written consent was taken from the respondents for the enrolment in the study. Privacy and confidentiality were maintained during and after the collection of data. No forceful participation was induced.

RESULTS
648 patients were screened for the study from Magh 2073 to Asar 2074, among them 114 were included for the analysis and rest of them were excluded. The main reason for exclusion were patients not meeting the inclusion criteria, referral to other center due to unavailability of bed, ventilator, left against medical advice, final diagnosis changed to malignancy. The included patients were either admitted or discharged from the emergency. They were admitted either in observation, or in ward or in intensive units (ICU, MICU, ICCU). They were followed up till discharge or mortality if any.

Baseline characteristics
The baseline characteristics of the cases were analyzed and arranged on the basis of the severity as per BAP 65 classes.

Relation Between BAP 65 Class and Mortality
We used Pearson Chi-squared test to compare between BAP 65 class and Mortality, and found that mortality rate increased with increasing BAP 65 class with a p value of < 0.0001.

Relation between admission in Intensive Units and BAP 65 Class
Out of 114 patients 19 patients were admitted in the intensive units. More than 75% patients were from Class IV and V, and the relation was found to be statistically significant based on Pearson Chi-squared test with a p-value of < 0.0001. This shows that with the increasing BAP 65 class the chance of getting admitted in the intensive units increases.

DISCUSSION
This study showed that mean age of the patients was 69.32±9.27 years with most of the cases belonging to 60-80 years of age group. The mean age of the patients is similar to the study conducted in Nepal Medical College Teaching Hospital, Nepal. 3 Similar findings were also noted in a study conducted in a Dutch population. 4 The minimum age observed was 44 years and the maximum being 93 years. About 2/3rd of the cases were older than 60 years which suggests that COPD is a disease of older age. The age distribution and mean age of the patients is similar to the study conducted in Latin America. 5 We observed that 34.2% were males and 65.8% were females. This finding varies among different countries. Study conducted in Nepal and various other developing countries shows that females are disproportionately affected by COPD, this may be due to extensive use of biomass fuel by women living in rural community which puts women at increased risk of exposure to indoor air pollution for comparatively longer periods of time. 1 This defers from the finding in developed world where there is a significantly lower prevalence of COPD in women than in men. 2,6 A meta-analysis of 62 population-based studies on prevalence for COPD published between 1990 and 2004 reported a pooled prevalence for COPD at 9.8% among men and 5.6% among women. 7 The most recent survey from an economically advanced country, Austria, found an equal prevalence of COPD in men and women. 8 Smoking and indoor air pollution are the well known risk factors for the development of COPD, we analyzed these risk factors in our sample and found that more than half of the patients were exposed to both the risk factors and 38 patients were current smoker. We analyzed the relation between intubated and non intubated patients with BAP 65 class and found it being statistically significant with p value <0.0001. We also found out that the severity of AECOPD increases when complicated by pneumonia, and the relation was statistically significant based on Pearson Chi squared test with a p value of < 0.0001. We further tested the relation between the individual variable and the primary end points based on Pearson Chi-squared test and the relation was found to be statistically significant except for age which poorly correlated with both the primary endpoints. These findings are similar with the study conducted by Tabet et al. 8

CONCLUSIONS
Based on these results, BAP 65 score is an effective scoring system in predicting the severity of AECOPD for the need of admission, need of intensive admission, need of mechanical