This measure shows the percentage of people aged 65 years and over who were dispensed five, six or seven unique long-term medicines.
Polypharmacy is associated with reduced adherence to therapies, significant costs to patients and health services, and poor health outcomes, such as adverse drug events, drug interactions, admissions to hospital and death. Older people (defined here as those aged 65 years and over) are more susceptible to medicine-related morbidity and mortality, especially those who are frail or have multiple co-morbid conditions.
PHO-enrolled population aged ≥ 65 years (on 30 June of each calendar year) who were dispensed same set of five, six or seven unique medications during a quarter of given year who were also dispensed in the quarter prior.
Numerator exclusions
- Therapeutic group 1: dermatologicals
- Therapeutic group 1: special foods
- Therapeutic group 1: sensory organs
- Therapeutic group 1, section C – extemporaneously compounded preparations and galenicals
- Therapeutic group 2: respiratory devices
- Therapeutic group 2: unknown (eg, header rows, named patient authority)
- Therapeutic group 2: various (eg, brand switch fee)
- Therapeutic group 2: diabetes management: ketone testing, blood glucose testing, insulin syringes and needles, insulin pumps, insulin pump consumables.
PHO-enrolled population aged ≥ 65 years (on 30 June of each calendar year).
Disaggregation detail
District analysis: By year (2019 –2023), age group (65–74 years; 75–84 years; 85 years and over), gender (female, male), ethnic group (Māori, Pacific peoples, Asian and European/other) and Health New Zealand district of domicile.
PHO analysis: By year (2023), age group, gender, ethnic group, Primary Health Organisation (PHO) most recently enrolled with (for the relevant year), PHO group (small, medium, medium-large and large).
A ‘long-term’ medicine was defined as the same medicine dispensed in two consecutive quarters.
Data is not presented where the number of people in the numerator was less than 10. This is to preserve confidentiality.
People were assigned to their Health New Zealand Te Whatu Ora district (previously referred to as Health New Zealand District Health Board; DHB) of domicile where more than one domicile was recorded in the calendar year, the most recent value was selected.
Age group is assigned using 30 June of each calendar year as the cutoff point. For example, a person turning 65 years old on 30 June 2023 will be assigned to the 65– 79 years age group for 2023, while a person turning 65 on 1 July 2023 will be assigned the 25–64 group for the same year.
Ethnic group data presented is prioritised ethnic group (Māori, Pacific peoples, Asian and European/Other).
Unlike other atlases, the Polypharmacy Atlas includes individuals who died during the calendar year in all indicators. This is because polypharmacy is higher among older adults and those in the final stages of life, due to chronic conditions, pain management, and palliative care needs.
For PHO analyses, we analysed indicator #1 to determine number of people who were dispensed a 5 or more medicines in two consecutive quarters among each PHO. Then we categorised them into small (<3,500 people), medium (between 3,500 and 7,000), medium-large (between 7,000 and 10,500) and large (>10,500 people).
People who were excluded from the analysis were:
- individuals with missing demographics– that is, those with no recorded value for one or more of the National Health Index (NHI) fields used to derive the demographic variables of interest (age, gender, ethnicity and district of domicile). For instance, a person with no recorded ethnicity in 2023 is excluded from all indicators for that calendar year. This approach ensures a consistent denominator throughout the analyses.
- those who weren’t enrolled in a PHO in the calendar year.