# Patient-Year(S) At Risk?

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Hello everyone,

After checking through web, I found that only a few website gave the definition. It might be context dependable but I'm not sure. One site says (quote) "Specifically identified in this publication as the ""annual death rate per 1,000 patient years at risk,"" it is the number of deaths for every 1,000 patient years on the waiting list. The rate is calculated by dividing the number of patients who died in a given year by the sum of the years (including partial years) that patients spent waiting and then multiplying by 1,000." Does this represent common understanding it ought to be or is there any other commonly understood definition? Am I still missing something to withdraw solid answer for what I am questioning in a vague tone here? Please guide me.

Many thanks,
No, do not multiply by 1000 to determine patient-years at risk. It is:

'the number of deaths for every 1 patient year on the waiting list. The rate is calculated by dividing the number of patients who died in a given year by the sum of the years (including partial years) that patients spent waiting.'

The confusion arises in that many statistics-- for example out-patient referral rates, death rates-- are calculated per 1000 patient-years.
Hi,

I think the formula from what I have seen looks like this:

Deaths per 1000 patient years=(number of deaths/(sum of all time spent on the patients on waiting lists))*1000

For example, if you had the following:

> 5 patients die
> 2400 months of time spent on waiting list by both patients who died and those those that did not
> 2400 months equals 200 years

Deaths per 1000 patient years = (5/200)*1000

Deaths per 1000 patient years = 0.025 * 1000

Deaths per 1000 patient years = 25

For every 1000 patient years spent on a waiting list, you could expect 25 deaths.

Looking at our original data, we see that there were 200 years with 5 deaths. So a using a simply ratio of 5 yields 1000 years and 25 deaths.

MountainHiker

p.s.: You should verify this formula with a medical professional.
Students: We have free audio pronunciation exercises.
Would you like to inform us in what period of time on waiting list do you calculate rate or how many time add each patient in waiting lis, since was incoming or since the initial year of the studied period ?