Table 1 Previous Studies

British Colombia (2006)

Morgan [24]

A population study on drug expenditure in 1996 and 2002 found 75 % of total drug costs were accounted for by 5 ATC groups in descending order of expenditure, ‘C’, ‘N’, ‘A’, ‘G’ (Genito Urinary System & Sex Hormones) and ‘J’ (Anti-infectives for Systemic Use).

Sweden (1998)

Gerdtham et al. [34]

This study identified ATC group ‘N’ contributed the most to drug expenditure.

Sweden (2004)

Gerdtham & Lundin [35]

This study identified ATC groups ‘N’, ‘C’ ‘and ‘A’ contributed the most to drug expenditure.

Sweden (2003)

Klarin et al. [36]

A study carried out on an elderly population (84+) found ‘C’, ‘N’ and ‘A’ were the most commonly prescribed drugs.

Spain (2011)

Vivas et al. [13]

This study reported the cost of drugs used to treat hyperlipidemia (from ATC ‘C’), respiratory illnesses, asthma (from ATC ‘R’) and diabetes (from ATC ‘A’) represents 37 % of total pharmaceutical expenditure on chronic conditions in Valencia.

Ireland (2006)

Naughton et al. [21]

A study based on an elderly Irish population (≥70 years) found that Cardiovascular Disease (CVD) is the most prevalent condition across all regions using a 2006 PCRS pharmacy database.

Various Studies

[3, 10, 20, 26, 30, 37]

A number of studies have identified age as a factor influencing pharmaceutical spending.

United States (1997)

Mueller et al. [30]

A study in the United States found the elderly (65+) accounted for 34 % of total pharmaceutical expenditure, children (≤17) accounted for 9 %, and those aged (18–64) accounted for the remaining 57 %. Of total drug expenditure, 41 % was spent on cardiovascular and renal drugs and 14 % on respiratory tract drugs.

3 European Countries (2008)

Sturkenboom et al. [20]

This study found that respiratory drugs were the most prescribed drugs and cardiovascular drugs were the least prescribed drugs for children (≤18).

Spain (2008)

Fernandez et al. [26]

A study in Catalonia, investigated how age influenced drug utilisation and found drug use was highest among infants (0–4) and those aged 55 and older.

Ireland (2015)

Conway et al. [10]

A recent study identified children (≤11) and the over 65 s as the two key drivers of future GMS costs in Ireland.

Various Studies

[2, 13, 23, 37]

Several studies have reported that females are more likely to utilise drugs than males.

United States (2000)

Steinberg et al. [37]

Males aged 65 and over were 50 % more likely not to be prescribed any drugs.

Sweden (2013)

Loikas et al. [23]

This study examined gender differences in drug prescribing and found 59 % of men and 76 % of women were dispensed at least one drug. Females were found to be prescribed more nervous drugs and males more lipid lowering (cardiovascular) drugs.

Various Studies

[12, 14, 15]

Geographical location is also considered in international studies as a predictor of pharmaceutical expenditure.

United States (2003)

Wrobel et al. [12]

A Medicare study examined the predictability of drug expenditure and found demographic variables (age, sex, disability & geographic location), explained only 5 % of the variation in drug expenditure. The inclusion of health status measures improved the explanatory power considerably.