Table Info

Table 3.

Current medications in the study groups

Variable	Adherent (n = 1,072)	Non-adherent (n = 79)	p-value
Medication overview, mean (SD)
Number of prescribed daily antihypertensive pills	2.26 (1.2)	2.65 (1.4)	0.006
Number of prescribed antihypertensive agents	2.89 (0.9)	3.10 (1.1)	0.058
Number of prescribed concomitant pills	2.46 (2.4)	2.65 (3.2)	0.499
Total number of prescribed daily pills^a	4.71 (2.9)	5.29 (3.8)	0.099
Antihypertensive medications, n (%)
ACEis	147 (13.7)	19 (24.1)	0.012
ACEi single-agent drug	86 (8.0)	14 (17.7)	0.006
ACEi combination with hydrochlorothiazide	51 (4.8)	4 (5.1)	0.787
ACEi combination with CCB	10 (0.9)	1 (1.3)	0.544
ARBs	894 (83.4)	58 (73.4)	0.024
ARB single-agent drug	242 (22.6)	19 (24.1)	0.762
ARB combination with hydrochlorothiazide	427 (39.8)	22 (27.8)	0.035
ARB combination with CCB	81 (7.6)	7 (8.9)	0.660
ARB triple combination (ARB + CCB + thiazide)	144 (13.4)	10 (12.7)	0.863
CCBs	740 (69.0)	64 (81.0)	0.025
CCB single-agent drug	505 (47.1)	46 (58.2)	0.056
Diuretics^b	694 (64.7)	41 (51.9)	0.022
Aldosterone antagonists	57 (5.3)	6 (7.6)	0.390
Beta-blockers	388 (36.2)	33 (41.8)	0.321
Alpha-adrenoreceptor blockers	36 (3.4)	5 (6.3)	0.169
Centrally acting sympathicolytics	47 (4.4)	4 (5.1)	0.777
Antihypertensive agents in single-agent or combination pills, n (%)
Only single-agent pills	348 (32.5)	34 (43.0)	0.054
Only 1 antihypertensive pill	296 (27.6)	11 (13.9)	0.008
Fixed-dose combination pill, one or more	724 (67.5)	45 (57.0)	0.054
Triple combination pill	144 (13.4)	10 (12.7)	0.863
Selected concomitant medications, n (%)
Lipid-lowering drugs^c	523 (48.8)	36 (45.6)	0.763
Anti-diabetic drugs^d	167 (15.6)	12 (15.2)	0.972
Anti-coagulants^e	386 (36.0)	31 (39.2)	0.391

Results are reported as n (%) or mean (SD), p-value denotes differences between the adherent and the non-adherent group. SD: standard deviation; ACEis: angiotensin converting enzyme inhibitors; CCB: calcium channel blocker; ARBs: angiotensin receptor blockers. ^a All antihypertensive pills + all concomitant pills; ^b diuretics include loop diuretics and thiazides; ^c lipid-lowering drugs include all cholesterol-lowering drugs; ^d antidiabetic drugs include oral antidiabetics and insulin; ^e anticoagulants include antiplatelet drugs and direct oral anticoagulants

Declarations

Acknowledgments

The authors thank the patients who participated in the study and the physicians who referred them.

Author contributions

EO: Investigation, Formal analysis, Writing—original draft. LVH and KMB: Investigation, Data curation. SR, AA, and OUB: Investigation. VNK: Investigation, Data curation, Validation. KL: Supervision. MDS, RM, EG, SEK, and AH: Project administration, Writing—review & editing. MR: Project administration. MSO: Methodology, Investigation. ACKL: Project administration, Data curation, Formal Analysis, Writing—review & editing, Funding acquisition. CLS: Project administration, Formal Analysis, Writing—review & editing, Supervision, Funding acquisition.

Conflicts of interest

Marit D. Solbu has received honoraria from AstraZeneca, Novartis, Bayer and Boehringer-Ingelheim. Sverre E. Kjeldsen reports lecture honoraria from Emcure, Getz, Glenmark, J.B. Pharma, Merck Healthcare KGaA, and Vector-Intas in the past 3 years. Sverre E. Kjeldsen is the Guest Editor of Exploration of Medicine but had no involvement in the decision-making or the review process of this manuscript. Aud Høieggen reports lecture honoraria from AstraZeneca. The other authors declare that there are no conflicts of interest.

Ethical approval

The study was approved by the Regional Ethical Committee of the UiT Arctic University in Norway, Tromsø, Norway (approval no. 2017/804/REK Nord) and complies with the Declaration of Helsinki.

Consent to participate

All participants signed written informed consent.

Consent to publication

Not applicable.

Availability of data and materials

Requests to the corresponding author in dire need.

Funding

The study was supported by grants from the Research Council of Norway [273563], the South-East Norwegian Regional Health Authority, the University of Oslo, Oslo University Hospital, Ullevaal, and the North Norwegian Regional Health Authority. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Copyright

Publisher’s note

Open Exploration maintains a neutral stance on jurisdictional claims in published institutional affiliations and maps. All opinions expressed in this article are the personal views of the author(s) and do not represent the stance of the editorial team or the publisher.

References

Fuchs FD, Whelton PK. High Blood Pressure and Cardiovascular Disease. Hypertension. 2020;75:285–92. [DOI] [PubMed] [PMC]

Mancia G, Kreutz R, Brunström M, Burnier M, Grassi G, Januszewicz A, et al. 2023 ESH Guidelines for the management of arterial hypertension The Task Force for the management of arterial hypertension of the European Society of Hypertension: Endorsed by the International Society of Hypertension (ISH) and the European Renal Association (ERA). J Hypertens. 2023;41:1874–2071. [DOI] [PubMed]

Chow CK, Teo KK, Rangarajan S, Islam S, Gupta R, Avezum A, et al. Prevalence, awareness, treatment, and control of hypertension in rural and urban communities in high-, middle-, and low-income countries. JAMA. 2013;310:959–68. [DOI] [PubMed]

Ashoorkhani M, Majdzadeh R, Gholami J, Eftekhar H, Bozorgi A. Understanding Non-Adherence to Treatment in Hypertension: A Qualitative Study. Int J Community Based Nurs Midwifery. 2018;6:314–23. [PubMed] [PMC]

Gavrilova A, Bandere D, Rutkovska I, Šmits D, Mauriņa B, Poplavska E, et al. Knowledge about Disease, Medication Therapy, and Related Medication Adherence Levels among Patients with Hypertension. Medicina (Kaunas). 2019;55:715. [DOI] [PubMed] [PMC]

Bergland OU, Halvorsen LV, Søraas CL, Hjørnholm U, Kjær VN, Rognstad S, et al. Detection of Nonadherence to Antihypertensive Treatment by Measurements of Serum Drug Concentrations. Hypertension. 2021;78:617–28. [DOI] [PubMed]

Weinstock RS, Trief PM, Burke BK, Wen H, Liu X, Kalichman S, et al. Antihypertensive and lipid-lowering medication adherence in young adults with youth-onset type 2 diabetes. JAMA Netw Open. 2023;6:e2336964. [DOI]

Halvorsen LV, Søraas CL, Larstorp ACK, Hjørnholm U, Kjær VN, Liestøl K, et al. Effect of therapeutic drug monitoring on adherence and blood pressure: a multicenter randomized clinical trial. Am J Hypertens. 2024;37:826–36. [DOI]

Parati G, Kjeldsen S, Coca A, Cushman WC, Wang J. Adherence to single-pill versus free-equivalent combination therapy in hypertension: A systematic review and meta-analysis. Hypertension. 2021;77:692–705. [DOI]

10.

Lam WY, Fresco P. Medication Adherence Measures: An Overview. Biomed Res Int. 2015;2015:217047. [DOI] [PubMed] [PMC]

11.

Lauder L, Ewen S, Kunz M, Richter LHJ, Jacobs CM, Kindermann I, et al. Adherence to antihypertensive drugs assessed by hyphenated high-resolution mass spectrometry analysis of oral fluids. J Am Heart Assoc. 2020;9:e014180. [DOI]

12.

Durand H, Hayes P, Morrissey EC, Newell J, Casey M, Murphy AW, et al. Medication adherence among patients with apparent treatment-resistant hypertension: systematic review and meta-analysis. J Hypertens. 2017;35:2346–57. [DOI] [PubMed]

13.

Siddiqui M, Judd EK, Dudenbostel T, Gupta P, Tomaszewski M, Patel P, et al. Antihypertensive medication adherence and confirmation of true refractory hypertension. Hypertension. 2020;75:510–15. [DOI]

14.

Thorstensen CW, Clasen PE, Rognstad S, Haldsrud R, Føreid S, Helstrøm T, et al. Development of UHPLC-MS/MS methods to quantify 25 antihypertensive drugs in serum in a cohort of patients treated for hypertension. J Pharm Biomed Anal. 2022;219:114908. [DOI]

15.

Kleinbaum DG, Morgenstern H, Kupper LL. Selection bias in epidemiologic studies. Am J Epidemiol. 1981;113:452–63. [DOI] [PubMed]

16.

Purssell E, Drey N, Chudleigh J, Creedon S, Gould DJ. The Hawthorne effect on adherence to hand hygiene in patient care. J Hosp Infect. 2020;106:311–7. [DOI] [PubMed]

17.

Rolnick SJ, Pawloski PA, Hedblom BD, Asche SE, Bruzek RJ. Patient characteristics associated with medication adherence. Clin Med Res. 2013;11:54–65. [DOI] [PubMed] [PMC]

18.

Corrao G, Zambon A, Parodi A, Poluzzi E, Baldi I, Merlino L, et al. Discontinuation of and changes in drug therapy for hypertension among newly-treated patients: a population-based study in Italy. J Hypertens. 2008;26:819–24. [DOI] [PubMed]

19.

Qvarnström M, Kahan T, Kieler H, Brandt L, Hasselström J, Boström KB, et al. Persistence to antihypertensive drug classes: A cohort study using the Swedish Primary Care Cardiovascular Database (SPCCD). Medicine (Baltimore). 2016;95:e4908. [DOI] [PubMed] [PMC]