Atrial Fibrillation , Clinical Profile and Adherence to Guidelines

Background: Even in developed countries suboptimal anticoagulation and low adherence to guidelines is frequently observed in Atrial fibrillation (AF) patients. There is no data from our regional population and very scarce Indian data about the utilization patterns and adherence to guidelines for stroke prevention in AF. Aims and Objectives: To characterize clinical profile and assess adherence to guidelines in stroke prevention in AF in north Indian population. Material and Methods: It was a single centre observational study. All patients presenting to outpatient department or admitted in cardiology wards from May 2014 to April 2016 with AF were included. Detailed history, examination and relevant investigations were carried out .CHADS2 score was used for risk stratifying and prescribing oral anticoagulants in nonvalvular AF. The effectiveness of oral anticoagulant was assessed by INR. Result: Total of 446 patients were included. Mean age of our patients was 60.83±16.86 years. 48% were males and 52% were females. Rheumatic heart disease was most common (37.2%) ethology followed by hypertensive cardiovascular disease (18.2%). Mean CHADS2 score was 2.63±1.5 in non valvular AF. Out of 446 patients, 409(92%) patients were found to have indication for prescription of OAC as per guidelines, out of which only 290 (71%) patients actually received OAC. OAC prescription was significantly higher in valvular vs. non valvular AF ( p=0.0001).The rates of OAC prescription in our patients in age group, ≤65, 66-75, >75 years were 84.4%, 65% and 60.2% respectively Out of 290 patients who were eligible for OAC ,only 102(25%) patients were optimally anti-coagulated. Conclusion: Discordance between guidelines and practice was found regarding prescription of OACs and maintenance of optimal anticoagulation for stroke prevention in our population. Optimal anticoagulation needs to be emphasized on both patients as well as physicians to prevent strokes and achieve better outcomes.


INTRODUCTION
Atrial fibrillation (AF) is the most common cardiac rhythm disturbance associated with frequent emergency department visits, hospitalizations, morbidity, mortality and serious economic consequences. 1The prevalence of AF is estimated at 1-2% in general population increasing with age 2,3 and as many as 9% of people older than 80 years are affected.AF accounts for 34.5% of patients hospitalized with a cardiac rhythm disturbances. 4he age adjusted prevalence is higher in men. 5 The total mortality rate is approximately double in patients with AF compared with patients with normal sinus rhythm and is linked to the severity of underlying heart disease.6 The risk of ischemic stroke among patients with non-rheumatic AF averages 5 % per year which is 2 to 7 times more than in people without AF.One out of six strokes occurs in patients with AF. 7 Prevention of thromboembolism is the main tenet of AF management and should begin with individual risk assessment of each patient. Cronic oral anticoagulation is currently the most effective therapy for attenuating the risk of stroke associated with atrial fibrillation Studies have shown that even in developed countries suboptimal anticoagulation is frequently observed 8,9,10,11 and adherence to guidelines 12 for prevention of stroke is poor.There is hardly any data from our regional population which has addressed this problem.There is very little Indian data .Small studies like CRAFT 13 from India have focused on treatment of Rheumatic AF only.This study was designed to meet this unmet need to assess to what extent our AF population is being prescribed appropriate stroke preventive measures and how successfully the present guidelines are being applied in this context.

AIMS AND OBJECTIVES
1. To study the clinical , etiological profile of AF 2. To assess whether anticoagulation for stroke prevention in AF is adhered to the current guidelines

Statistical analysis
Continuous variables were expressed as mean± standard deviation and categorical variables as percentages.Differences in continuous variables between the two groups were evaluated with unpaired t test and differences in categorical variable, were evaluated using Fisher's exact test.
A p-value of less than 0.05 was considered as statistically significant.Data analysis was done using SPSS 20 version software.

RESULTS
The mean age of our patient cohort was 60.83±16.86years (range of 16 to 90).The median age was 65 years.Of total 446 patients who had atrial fibrillation, 48% (214) were males and 52% (232) were females.Males were older than the females and this difference was statistically significant (62.84±17.8vs 58.97±15.7,p value 0.015).In our study, rheumatic heart disease (RHD) was the most common etiology (37.2 %) followed by hypertensive cardiovascular disease (HTCVD) (18.2%),CAD in 15.9%, dilated cardiomyopathy in 12.8% (Table 1).Prevalence of RHD was significantly higher in females as compared to the males (41.8% vs 32.2%, p value 0.037).Whereas prevalence of CAD (19.6% vs 12.5%, p value 0.04) and COPD (4.7% vs 0.9%, p value 0.03) was significantly higher in males compared to females.When studying the associated risk factors in our patients, we found that 63.9 % (285) of our patients were hypertensive, 33% (147) were smokers and both these factors were significantly more commonly seen in males.Diabetes mellitus was present in 15% (67) patients and 7.2% (32) had renal dysfunction associated (Table 2).Systolic LV dysfunction (LVEF<50%) was documented in 16.5% (73) patients.67.5% (301) of our total patients were seen to have left atrial( LA) size more than 4cm while 33.9% (151) patients had LA size more than 5.0 cm.The mean LA size of our patient population was 4.7±1.3cm.Out of total 446 patients, valvular AF (rheumatic and non-rheumatic) was seen in 179 (40%) patients.Rest of 267(60%) patients had a non-valvular etiology for their AF.These 267 patients were risk stratified for stroke risk using CHADS 2 score.Figure 1 show the CHADS 2 score ranging from 0 to 6. Majority of patients had a score of 2 and 3 which accounted for 63.3% of total non-valvular AF patients (Figure1).Mean CHADS 2 score was 2.63±1.

DISCUSSION
The present study is the first prospective study assessing clinical profile of the patients with AF and adherence to guidelines for stroke prevention in our region.We noted that females formed 52% of AF cohort which is in accordance with, (56.4% females ) 14 and (51.04% females). 15However in various other studies prevalence of AF was higher in males. 16,17Mean age of our patient population was 60.83±16.86years.Males were significantly older than females (62.84±17.84vs 58.97±15.71p=0.015).Mean age of presentation of AF was higher in our population as compared to in various other studies but is comparable with (69.8±11.8years) 17 and (65 years). 18n our study 403 (90.35%) out of 446 patients had underlying cardiac disorder.Valvular heart disease (40.1%) including both rheumatic (37.2%) as well as non-rheumatic(2.9%)was the most common etiological factor in our patient population followed by hypertensive cardiovascular disease (HTCVD) (18.1%), coronary artery disease (CAD) (15.9%), dilated cardiomyopathy (DCM) (12.8%) and Idiopathic (lone AF) accounted for 5.4% .Our study is in contrast to various studies 16,17,20 in which HTCVD is the most common etiology and rheumatic valvular disease comes much lower down.This reflects the increased prevalence of RHD in our population.Similar results were found in a study done in rural Bihar in which RHD accounted for 51.5% of patient.
The risk factors which were associated with AF in our study included hypertension 285(63.9%),smoking 147(33%), LV dysfunction 73(16.4%),diabetes 67(15%) and renal insufficiency 32(7.2%).LA size >4cm was seen in 301 (67.5%) patients.Mean LA size was 4.7±1.3cm.Hypertension was the most common associated condition as seen in various other studies. 14,15,17,21evention of thromboembolism is the main tenet of AF management and should begin with individual risk assessment of each patient.We used CHADS 2 score to risk stratify the patients with non-valvular AF.Of 446 patients, 267 patients had non-valvular cause of AF.Mean CHADS 2 score in our non-valvular patient population was 2.61±1.2.95.5% (255) of 267 patients had CHADS 2 score ≥1 while 86.1% (230) patients had CHADS 2 score of ≥ 2. The mean CHADS 2 score varied from 1.9±1.1 to 1.33±1.24 in various studies. 14,17,22t of 446, 409 (91.7%) patients in our study population had indication for receiving OAC (oral anticoagulation) while 37 (8.3%) patients did not have indication for OAC according to current guidelines.The rate of prescription (71.9%) of OAC to our patients was considerably higher in our study as compared to other studies. 14,15,16However it was more in agreement with 67% 18 and 60% 23 In a study by, 17 among patients with an indication for OAC, 88% (403/458) effectively received it. 17This study had one of highest rate of OAC prescriptions.A higher and good rate of OAC prescription in our study population may be due to the fact that in our hospital all AF patients are followed and treated by experienced cardiologists.
We also found that our OAC prescription decreased as age increased.
The rates of OAC prescription in our patients in age group, ≤65, 66-75, >75 years were 84.4%, 65% and 60.2% respectively which was in stark contrast to study done by Meiltz et al in which the rate increased from 72% in ≤65 years group to 87% in >75 years group.However, this negative effect of age on rate of OAC prescription has been seen in many other studies by. 23,24,25The fact of the matter is that chances of stroke increase with increasing age and it is this population of elderly people who derive the maximum benefits of stroke prevention with OAC.However, the results of our and various other studies reflect the mindset and fear of bleeding in elderly which needs to be corrected to pass on the full benefits to this high risk group of patients.We also found that OAC prescription was significantly higher in valvular vs. non valvular AF (p=0.0001).This may reflect poor application of CHADS 2 score in risk stratifying patients by the treating physicians.

Figure 1 :
Figure 1: Bar diagram showing frequency of CHADS2 score with respect to sex.

Table 1 : Table showing etiological profile in AF patients
5. Out of these 267 patients, 230 (86.14%) patients had CHADS 2 score of ≥2 thereby implying the need for oral anticoagulants as the preferred modality for stroke prevention .Overall, 23.3% (104) of our patients received anti-platelets.49.6% (221) patients received oral anticoagulants ( OAC) and 19.1% (85) received both OAC and anti-platelets.Significantly, 8.1% (36) patients did not receive any form of stroke prevention therapy-neither aspirin nor OAC (Table3).Out of 446, 409 (91.7%) patients in our study population had indication for receiving OAC and 37 (8.3%) patients did not have indication for OAC according to current guidelines .Of total 409 patients having indication for OAC, 290 (70.9%) received OAC whereas 119 (29.1%) did not receive it despite being eligible.Of 37 patients who had no indication for OAC, 16 patients received OAC.A total of 306 patients received OAC.Out of 306 patients who received OAC, 61.4% patients were found to be inadequately anticoagulated whereas 35.6% were optimally anticoagulated, rest of the patients were over anticoagulated.