Objective: To describe medication use among older community-dwelling Icelanders by collecting information on number of medicine, polypharmacy (>5 medications), and medications by ATC categories. Moreover, to explore the relationship between medication use and various influential factors emphasizing residency in urban and rural areas.

Material and methods: Population-based, cross-sectional study. Participants were randomly selected from the National registry in one urban (n=118) and two rural (n=68) areas. Inclusion criteria: 1) ≥65 years old, 2) community-dwelling, 3) able to communicate verbally. Information on medication use was obtained from each person's medication list and interviews. A questionnaire and five standardized instruments were used to assess the potential influencing factors.

Results: On average, participants used 3.9 medications and prevalence of polypharmacy was 41%. Men used 3.5 medications on average and women 4.4 (p=0.018). Compared to rural residents, urban residents had fewer medical diagnoses, better mobility, less pain, and fewer depressive symptoms. By controlling for the effects of these variables, more medications were associated with urban living (p<0.001) and more medical diagnoses (p<0.001). Likewise, adjusted odds for polypharmacy increased with urban residency (p=0.023) and more medical diagnoses (p=0.005). Urban residency, more medical diagnoses, higher age, and male gender were related to use of drugs for blood and blood forming organs.

Conclusion: The results reveal an unexplained regional difference in medications use by older Icelanders. Further studies are required on why urban residents use at least equal amount of medications as rural residents despite better scores on health assessments.

Table I. Description of participants, contextual factors and medication use.
	Mean (standard deviation) [range] or number (%*)			p‡
	Total † N = 186	Urban n = 118	Rural n = 68
Age, years	74 (6,3)[65-88]	74 (6,3) [65-88]	74 (6,2) [65-86]	0,658
Age group:
65-74 years	114 (61%)	73 (62%)	41 (60%)
75-88 years	72 (39%)	45 (38%)	27 (40%)	0,832
Gender:
Woman	89 (48%)	62 (52%)	27 (40%)
Man	97 (52%)	56 (48%)	41 (60%)	0,091
Education, years	7,5 (3,3) [0-20]	8,2 (3,6) [0-20]	6,3 (2,2) [3-13]	<0,001
Adequate income	123 (66%)	88 (75%)	35 (52%)	<0,001
Living alone	45 (24%)	35 (30%)	10 (15%)	0,022
Home nursing service	16 (9%)	10 (9%)	6 (9%)	0,949
Social domestic service	63 (34%)	39 (33%)	24 (35%)	0,787
Number  of diagnosed diseases	3,2 (1,8) [0-9]	2,7 (1,6 [0-7]	4,1 (1,8) [0-9]	<0,001
Body mass index (BMI), kg/m2	27 (3,8) [17-39]	27(3,8) [17-39]	27(3,6) [19-36]	0,872
Physical activity (PASE), 0-400+	127 (92) [0-513]	126(87) [0-425]	130(101) [0-513]	0,782
Physical function (TUG), sek	11 (3,6) [5-24]	10 (3,4) [5-24]	12 (3,4) [7-23]	<0,001
Pain (SF-36), 0-100	65 (41) [0-100]	73 (40) [0-100]	50 (37) [0-100]	<0,001
Depressive symptoms (GDS), 0-30	6,5 (4,3) [1-20]	5,6 (3,8) [1-20]	8,1 (4,6) [1-20]	<0,001
Cognitive function (MMSE), 0-30	27 (2,5) [16-30]	27 (2,5) [16-30]	27 (2,7) [21-30]	0,793
Number of medicine	3,9 (2,7) [0-12]	4,0 (2,8) [0-12]	3,8 (2,6) [0-11]	0,622
Polypharmacy (≥ 5 drugs)	76 (41%)	47 (40%)	29 (43%)	0,707
* Proportions (%) are based on valid data for each variable; †based on nonweighted data; ‡ p values indicate the significance of differences between rural and urban participants; PASE = Physical Activity Scale for the Elderly; TUG = Timed Up and Go; SF-36 = Short Form 36-item health survey; GDS = Geriatric Depression Scale; MMSE = Mini-Mental State Examination.

 

Table II. Comparison of ATC medication use, in 13 ATC categories, by urban and rural residency.
ATC-group	Total* n =186	Urban  n=118	Rural  n=68	p†
A – Alimentary tract and metabolism	65 (34,9%)	40 (33,9%)	25 (36,8%)	0,693
B – Blood and blood forming organs	67 (36%)	46 (39%)	21 (30,9%)	0,268
C – Cardiovascular system	123 (66,1%)	78 (66,1%)	45 (66,2%)	0,902
D - Dermatologicals	1 (0,5%)	0 (0%)	1 (1,5%)	0,187
G – Genito-urinary system and sex hormones	15 (8,1%)	9 (7,6%)	6 (8,8%)	0,773
H – Systemic hormonal preparations, excluding sex hormones and insulins	23 (12,4%)	15 (12,7%)	8 (11,8%)	0,850
J – Antiinfectives for systemic use	5 (2,7%)	2 (1,7%)	3 (4,4%)	0,270
L – Antineoplastic and immunomodulating agents	4 (2,2%)	1 (0,8%)	3 (4,4%)	0,107
M – Musculo-skeletal system	42 (22,6%)	25 (21,2%)	17 (25%)	0,549
N – Nervous system	69 (37,1%)	43 (36,4%)	26 (38,2%)	0,807
P – Antiparasitic products, insecticides and repellents	1 (0,5%)	0 (0%)	1 (1,5%)	0,187
R – Respiratory system	22 (11,8%)	16 (13,6%)	6 (8,8%)	0,335
S – Sensory organs	6 (3,2%)	1 (0,8%)	5 (7,4%)	0,016
*Based on nonweighted data; †  p values indicate the significance of differences between medication use in urban and rural areas.

 

 

Table III. Independent association between nine explanatory factors and the four most prevalent ATC classifications. The four multivariate models are based on logistic regression analysis on weighted data.
	Alimentary tract and metabolism		Blood and blood forming organs		Cardiovascular system		Nervous system
	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI
Gender (0 = woman, 1 = man)	0,72	0,33 – 1,6	3,65**	1,53 – 8,71	1,11	0,47 – 2,63	0,91	0,37 – 2,22
Recidency (0 = rural, 1 = urban)	1,31	0,58 – 2,99	2,99*	1,16 – 7,71	2,18	0,85 – 5,58	2,12	0,83 – 5,42
Age	1,04	0,97 – 1,12	1,15**	1,06 – 1,25	1,06	0,97 – 1,16	1	0,92 – 1,08
Cognitive function (MMSE)	0,98	0,81 – 1,19	0,91	0,77 – 1,08	0,88	0,72 – 1,09	0,88	0,75 – 1,03
Depressive symptoms (GDS)	1,02	0,91 – 1,4	1	0,87 – 1,13	0,91	0,75 – 1,11	1,26**	1,09 – 1,45
Physical function (TUG)	0,92	0,81 – 1,06	1,01	0,89 – 1,15	1,01	0,85 – 1,17	1,02	0,87 – 1,21
Physical activity (PASE)	1	0,99 – 1,01	1	0,99 – 1,01	1	0,99 – 1,01	0,99*	0,98 – 0,99
Pain (SF-36)	1	0,99 – 1,01	1	0,99 – 1,01	1	0,99 – 1,01	0,99	0,98 – 1
Number of diagnosed diseases	1,31	1– 1,72	2,42*	1,06 – 1,81	1,97**	1,3 – 2,92	0,96	0,7 – 1,33
OR = Odds Ratio; CI = Confidence Interval; MMSE = Mini-Mental State Examination; GDS = Geriatric Depression Scale; TUG = Timed Up and Go; PASE = Physical Activity Scale for the Elderly; SF-36 = Short-Form Health Survey; * p < 0,05; ** p < 0,01.