Question

Cigarettes/Day	Death Rate/1000/Year due to CHF Males	Death Rate/1000/Year due to CHF Females
0	0.01	0.008
1-14	0.27	0.11
15-24	1.23	1.15
25+	2.00	1.50

1. Your team would like to calculate the attributable risk or attributable proportion of CHF death rates due to smoking 1-14 and 15-24 cigarettes per day separately for males and females. Do you notice any differences within and between these groups in death rates due to CHF based on the different number of cigarettes smoked per day?
2. What can the team conclude about the death rate due to CHF for males and females separately when zero cigarettes per day are smoked? How do they compare?

   Your quality improvement Team is revisiting the following patient readmissions and would like to predict the number of readmissions based on the number of drugs administered.

Answer 1

a) Population Attributable Proportion (PAP) or Population Attributable fraction (PAF) = (proportion of cases exposed) x (attributable proportion in the exposed)

This is the proportion (fraction) of all cases in the population that can be attributed to the exposure.

can be calculatd as follows,

where P_pop = the proportion of exposed subjects in the entire study population, and RR = the risk or rate ratio.

For male 1-14,

RR=.27*1000= 270

P_pop=0.27

AF= 0.27*(270-1)/0.27*(270-1)+1 = 0.9864 or 98.64%

For Female 1-14,

RR=.11*1000= 110

P_pop=0.11

AF= 0.11*(110-1)/0.11*(110-1)+1 = 0.9230 or 92.30%

For male 15-24,

RR=1.23*1000= 1230

P_pop= 1.23

AF= 1.23*(1230-1)/1.23*(1230-1)+1 =0.9993 or 99.93%

For Female 15-24,

RR=1.15*1000= 1150

P_pop= 1.15

AF= 1.15*(1150-1)/1.15*(1150-1)+1 =0.9992 or 99.92%

on comparison e can see in group 1-14 The AP is too high for males (98%) on death rate 0.27 but on females while the death rate is almost less than half of the males ie 0.11 but again the AP is relatively high enough (92%).

b)

for 0 cigretes,

Again we will see it by AP,

For male,

RR=.01*1000= 10

P_pop=0.01

AF= 0.01*(10-1)/0.01*(10-1)+1 = 0.0825 or 8.25%

For female,

RR=.008*1000= 8

P_pop=0.008

AF= 0.008*(8-1)/0.008*(8-1)+1 = 0.0530 or 5.30%

Again, comparing based on the AP we see the risk is minimal in both males and females which is self justifiable too. as the no. of deaths per year are too low.