Example of index calculation

As calculated for Iisalmi

The morbidity index is based on the following three statistical and register variables:

  • mortality rate (as a percentage of the population)
  • share of 16 to 64 year-olds who are on disability pension
  • share of the population entitled to special rate of reimbursement on medicine costs.

About one percent of the population dies in a given year. In smaller municipalities, the number of deaths may fluctuate greatly from year to year, while the mortality rate stays constant in the long term. The index is therefore calculated as an average for three consecutive years, or in this case, the years 2009–2011.

The other two variables are based on register data which change relatively little year to year. Even small municipalities will have a requisite volume of cases so that it is possible to refer to the most recent available statistical year. The most recent year for which statistical data for the indices are available is 2011.

Mortality rate

The mortality rate is derived by calculating the number of deaths as a percentage of the regional population.

An average of 235.67 persons in the Iisalmi population died in the years 2009–2011. The population average for Iisalmi in 2009–2011 was 22,176. The mortality rate was thus 100 x 235.67 ÷ 22,176, or 1.0627%.

The average number of deaths in the Finnish population was 48,251 in 2009–2011. Relative to the total population during the period in question, the mortality rate for the country as a whole is 0.93930%.

The mortality index for Iisalmi was therefore 100 x 1.0627 ÷ 0.93930 =1113.1.

Disability

A total of 1,406 persons in Iisalmi were in receipt of a disability pension from either earnings-related pension scheme or from Kela in 2011. Relative to the working-aged population (14,042), the prevalence of disability pensions was 10.013%.

In the whole country, a total of 253,483 persons received a disability pension during the period in question, which was 7.3031% of the total working-aged population (3,470,893 persons).

The disability index for Iisalmi was therefore 100 x 10.013 ÷ 7.3031 = 137.1.

Entitlements to reimbursement of pharmaceutical expenses

At the end of 2011, 7,041 Iisalmi residents were entitled to reimbursements for medicines or dietary products. Relative to the municipal population in 2011 (22,160 persons), the share of the persons entitled to reimbursements was 31.773%.

In the country as a whole, the corresponding figures were 100 x 1,313,954 ÷ 5,401,338, which means that 24.326% of the population was entitled to a special rate of reimbursement on medicines or dietary products at the end of the year.

Representing the prevalence of chronic illnesses, the index of entitlement to special reimbursement in Iisalmi is therefore 100 x 31.773 ÷ 24.326 = 130.6.

Morbidity index

The general index is calculated as the unweighted mean of the three subindices. The non-standardised morbidity index for Iisalmi in 2011 was therefore (113.1 + 137.1 + 130.6) ÷ 3, or 126.9.

Indices standardised for age and sex

Age-and-sex standardisation can be used to account for large regional differences in the population’s age structure. The standardised index shows what the morbidity index for Iisalmi or any other municipality would be if the age structure in the municipality were the same as in the country at large. The morbidity index standardised for age and sex is a starting point for follow-up study in that it provides insight into how much of morbidity is due to other reasons than variations in the population’s distribution by age and gender.

In the Health Barometer, the direct method is used to standardise for age and gender. The population between 0 and 84 years of age is divided into gender-specific age quintiles. The oldest category includes everyone 85 years of age or older. In calculating the index standardised for age and sex, the number of persons who have died, are on disability pension, or are entitled to a special rate of reimbursement on medicine costs are weighted to reflect the age structure of the whole country. The standard population is the total population of the country, except in the case of the disability index, where it is the population between ages 16 and 64.

Example indices for Iisalmi (2011) in the Health Barometer )