Abstract
The authors investigated antihypertensive drug treatment in Sweden using the Stockholm Regional Healthcare Data Warehouse, providing information on all healthcare consultations, diagnoses, hospitalizations, dispensed prescription drugs, sex, and age in 2.1 million persons. This cross‐sectional analysis identified 292 428 individuals 20 years or older with hypertension (mean age 68 ± 13 years, 53% women). About half had no diabetes mellitus or cardiovascular comorbidity. The number of dispensed drugs was lower in women than in men (1.9 ± 1.3 vs 2.1 ± 1.5, P < .001). Women more often used diuretics, angiotensin receptor blockers, and β‐blockers, while men used more angiotensin‐converting enzyme inhibitors and calcium channel blockers (all P < .01). In women, 66% with diabetes mellitus and 72% with heart failure used angiotensin‐converting enzyme inhibitors/angiotensin receptor blockers vs 76% and 79% in men (all P < .001, adjusted for age and comorbidity). Thus, sex differences in treatment prevail. There is room for improvement, which could reduce cardiovascular complications.
Keywords: antihypertensive agents, blood pressure, cardiovascular disease, diabetes mellitus, sex, hypertension, primary health care, treatment
1. INTRODUCTION
Hypertension is common, with an estimated prevalence of 27% in the adult Swedish population1 and similar rates reported in North American (28%) and European (44%) countries and globally (22%).2, 3 Hypertension is the major global cause of premature death.4, 5 Thus, it is important to improve the recognition and treatment of hypertension. Several large trials have clearly demonstrated that blood pressure reduction by antihypertensive drug therapy substantially reduces the risk of nonfatal and fatal cardiovascular events.6, 7, 8 The benefit of antihypertensive treatment appears to be similar in women and men.9, 10 However, less than half among treated patients achieve target blood pressure.11, 12 Thus, it is important to study current drug prescription in clinical practice to identify areas for improvement.
Antihypertensive drug treatment has changed during the past years for several reasons. The introduction of newer drug classes such as angiotensin‐converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and calcium channel blockers (CCBs) and subsequent changes in guidelines recommendations13, 14; patents expiring and subsequent generic substitution at much lower costs; and decisions by authorities on which drugs are included in the national reimbursement scheme15 have all had a major impact on the choice of antihypertensive drugs prescribed.
The majority of patients with hypertension are treated in primary care practices in many countries including Sweden, and this is the basis of healthcare systems in many countries.16 However, most studies on the treatment of hypertension in primary care in Sweden and elsewhere were based on small populations or used self‐reported data from questionnaires, with potential confounding.17, 18 Thus, we still lack robust knowledge about current management of patients with hypertension in primary health care and information on treatment, drug use, and comorbidity. To address these important issues, we performed a large retrospective study using the data from the largest administrative health data register in Sweden (the Stockholm Regional Healthcare Data Warehouse; Vårdanalysdatabasen [VAL])19, 20 comprising more than 2.1 million inhabitants, to describe current antihypertensive drug treatment in relation to sex, comorbidity, and age.
2. METHODS
2.1. Study population
This cross‐sectional study included all 292 623 persons 20 years or older with a recorded primary or secondary diagnosis of hypertension (International Classification of Diseases, Tenth Edition: I10, I13, or I15) any time between 2009 and 2013 in the greater Stockholm region, Sweden. The prevalence of diagnosed hypertension was calculated from data obtained from Statistics Sweden divided by the population and stratified for 10‐year age intervals for the same geographic region. We collected information on comorbidity (International Classification of Diseases, Tenth Edition), including diabetes mellitus (E10‐11), previous stroke/transient ischemic attack (I60‐69 or G45), ischemic heart disease (I20‐25), congestive heart failure (I50), atrial fibrillation or flutter (hereafter termed atrial fibrillation; I48), and asthma/chronic obstructive pulmonary disease (J40‐45). We also collected data on dispensed antihypertensive drugs in 2013. A filled prescription was considered as a dispensed drug. The drug classes recorded (with corresponding Anatomic Therapeutic Chemical classification system codes) were ACEIs (C09A), ARBs (C09C), β‐blockers (C07), CCBs (C08), and diuretics (C03A‐C03E); amiloride was considered a diuretic, whereas mineralocorticoid receptor antagonists (MRAs) were recorded separately. Other antihypertensive drugs (C02) were mostly doxazosin and moxonidine. Fixed‐dose combinations were considered as two separate drug classes.
The study was approved by the regional ethical review board in Stockholm.
2.2. Data sources
The population of Stockholm County represents more than one fifth of the entire population in Sweden (currently approximately 10 million persons). The Stockholm Regional Healthcare Data Warehouse provides information on all healthcare consultations in primary and secondary care (defined as specialist outpatient care), diagnoses (according to International Classification of Diseases, Tenth Edition), all hospitalizations with diagnoses and procedures, and sex and age. It contains encrypted, anonymized data linked through the unique identifier (personal identification number) of each patient.21 The information from hospitals correspond to the information in the National Patient Registry, managed by the National Board of Health and Welfare, which includes hospital discharges on a national level since 1964 and is well validated.22 In addition, the Stockholm regional register contains data on consultations with diagnoses recorded in primary care since 2004. Data on dispensed prescription medicines correspond to the national Prescribed Drug Register held by the National Board of Health and Welfare, which contains data on all prescription drugs dispensed in Sweden since July 2005, the age and sex of the patient, prescriber category, amounts and dosages, expenditures, and reimbursement.23 It has a high validity, as more than 99% of all prescriptions are recorded with unique identifiers of each patient.
2.3. Statistical methods
Means ± standard deviations and proportions were used to describe the study population. Differences between groups were assessed by Student’s t or Mann‐Whitney tests for continuous variables and chi‐square test for categorical variables, as appropriate. Group comparisons with adjustment for age and comorbidity (ie, diabetes mellitus, ischemic heart disease, heart failure, cerebrovascular disease, and atrial fibrillation) were performed by analysis of covariance. A probability P < .05 was considered significant. Statistical analyses were performed using STATA software, version 13.1.
3. RESULTS
3.1. Patient demographics
There were 154 230 (53%) women and 138 393 (47%) men with a recorded diagnosis of hypertension. With approximately 2.1 million persons living in the region in 2013, this corresponds to a prevalence of diagnosed hypertension of 14%. The mean age of those alive in 2013 was 69.5 ± 13.4 years in women and 66.0 ± 12.6 years in men; with an age range from 20 to 109 years. The age distribution and prevalence according to age group is shown in Figure 1. There was a greater representation of women among patients 70 years and older. Of note, more than 12 000 patients were 90 years and older in this cohort.
Figure 1.
Prevalence of diagnosed hypertension, according to age and sex. The solid line represents the total number of patients with hypertension per age group. The filled bars represent women and the open bars men.
The majority (87%) of the patients had their hypertension diagnosis recorded in primary health care at least once during the years 2009 to 2013 (Figure 2). Approximately half of the patients had a hypertension diagnosis recorded in primary care only. Although many patients also visited specialist care, as few as 14% of all patients with hypertension had the diagnosis recorded in hospitals or outpatient specialist care only.
Figure 2.
Proportion of patients attending different care providers. Data for 292 623 patients with a recorded diagnosis of hypertension in the greater Stockholm region, Sweden, any time during the years 2009–2013, who were alive at the end of 2013. There is an overlap between primary health care, specialist ambulatory care, and inpatient care.
3.2. Hypertension and comorbidity
The most common comorbidities among men were diabetes mellitus, ischemic heart disease, and atrial fibrillation (Figure 3). In women, the most common comorbidities were diabetes mellitus, asthma/chronic obstructive pulmonary disease, and ischemic heart disease. Approximately half of the patients were free of a diagnosis of cardiovascular comorbidity. There were relatively few patients with hypertension with more than one comorbidity. For example, concomitant ischemic heart disease and diabetes mellitus combined was present in 3% of the women and 6% of the men, and concomitant ischemic heart disease and heart failure combined was present in 3% of the women and 4% of the men.
Figure 3.
Comorbidity for women 154 230 women and 138 393 men with a recorded diagnosis of hypertension in the greater Stockholm region, Sweden, any time during the years 2009–2013. No cardiovascular or diabetic comorbidity was recorded in 56.3% of women and 48.9% of men. AF indicates atrial fibrillation or flutter; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; HTN, hypertension; IHD, ischemic heart disease; TIA, transient ischemic attack.
3.3. Drug treatment
The most common dispensed antihypertensive drug classes overall (as monotherapy or in combination) in men were β‐blockers, ACEIs, and CCBs, (Table 1). In women, however, the most common drug classes were β‐blockers, ARBs, and diuretics (Table 1). The use of MRA was 3% in both women and men. Few patients (0.4% in women and 1.1% in men) received other antihypertensive drug classes (ie, C02), which was mostly doxazosin (90%) and moxonidine (8%) in combination with other antihypertensive treatment.
Table 1.
The most commonly dispensed antihypertensive drug classes
| Drug class | Women, % | Men, % |
|---|---|---|
| Most common drugs (as single drug or used in combination) | ||
| β‐Blockers | 39 | 38 |
| Diuretics | 38 | 32 |
| CCBs | 29 | 34 |
| ACEIs | 27 | 36 |
| ARBs | 30 | 29 |
| MRAs | 3 | 3 |
| Other drugs | 0.4 | 1.1 |
| Most common drug combinations | ||
| β‐Blocker + diuretic | 17 | 15 |
| β‐Blocker + CCB | 13 | 16 |
| β‐Blocker + ACEI | 11 | 16 |
| β‐Blocker + ARB | 12 | 12 |
| ARB + CCB | 8 | 14 |
| ARB + diuretic | 16 | 15 |
| CCB + diuretic | 12 | 13 |
| ACEI + diuretic | 11 | 14 |
| ACEI + CCB | 9 | 11 |
The most commonly dispensed antihypertensive drug classes in 2013 in 154 230 women and 138 393 men with a recorded diagnosis of hypertension. ACEIs indicates angiotensin‐converting enzyme inhibitors; ARBs, angiotensin receptor blockers; CCBs, calcium channel blockers. Amiloride was considered a diuretic, whereas mineralocorticoid receptor antagonist (MRA) was recorded separately. Other antihypertensive drugs were mostly doxazosin (90%) and moxonidine (8%). All differences between women and men were significant (P < .01).
Women were more often treated with diuretics, ARBs, and β‐blockers, whereas men were more often treated with ACEIs and CCBs (P < .01 for all; Table 1). In 4% of the patients, both an ACEI and an ARB were dispensed during 2013. The numbers of drug classes used were lower in women than in men (1.9 ± 1.3 vs 2.1 ± 1.5, P < .001). This was consistent across different age groups.
The dispensed drug classes according to age and sex are presented in Figure 4. The use of β‐blockers, diuretics, and MRA was more common with older age, whereas the use of ACEIs, ARBs, and CCBs decreased with older age.
Figure 4.
Dispensed drug classes, according to sex and age for 292 623 patients with a recorded diagnosis of hypertension in the greater Stockholm region, Sweden, any time during the years 2009–2013. Amiloride was considered a diuretic, whereas mineralocorticoid receptor antagonist (MRA) was recorded separately. Other antihypertensive drugs were mostly doxazosin and moxonidine. ACEI indicates angiotensin‐converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker.
Compared with patients with no cardiovascular disease or diabetes mellitus, the use of β‐blockers was more common in patients with ischemic heart disease, atrial fibrillation, and heart failure (70%, 74%, and 71%, respectively) (Table 2). In patients with diabetes mellitus and previous stroke/transient ischemic attack, CCB use was more common. ACEIs and ARBs were more common in patients with hypertension with heart failure and diabetes mellitus. Thus, ACEIs or ARBs were used in 66% of women and in 76% of men with concomitant heart failure, and in 72% of women and in 79% of men with diabetes mellitus (P < .001, adjusted for age and comorbidity). The use of MRA and diuretics were more common in patients with concomitant heart failure and atrial fibrillation.
Table 2.
Proportion of patents and dispensed antihypertensive drug classes according to comorbidity
| ACEIs | ARBs | CCBs | β‐Blockers | Diuretics | MRAs | |
|---|---|---|---|---|---|---|
| Women | ||||||
| No cardiovascular disease | 25.0 (24.8–25.3) | 29.4 (29.1–29.7) | 27.6 (27.3–27.8) | 30.5 (30.2–30.8) | 34.7 (34.4–35.1) | 1.6 (1.5–1.7) |
| Ischemic heart disease | 29.9 (29.2–30.6) | 30.3 (29.6–30.9) | 32.3 (31.6–33.0) | 68.0 (67.3–68.7) | 49.6 (48.8–50.5) | 7.3 (7.0–7.7) |
| Atrial fibrillation | 29.7 (28.9–30.4) | 30.3 (29.6–31.1) | 28.0 (27.3–28.7) | 76.5 (75.8–77.1) | 59.5 (58.5–60.4) | 11.3 (10.8–11.8) |
| Congestive heart failure | 36.335.4–37.1) | 29.9 (29.1–30.8) | 25.1 (24.3–25.9) | 69.6 (68.7–70.4) | 73.672.6–74.6) | 17.3 (16.6–17.9) |
| Cerebrovascular disease | 30.3 (29.3–31.3) | 27.2 (26.2–28.2) | 32.8 (31.8–33.8) | 49.6 (48.2–50.3) | 44.5 (43.4–45.7) | 5.5 (5.0–6.0) |
| Diabetes mellitus | 35.7 (35.1–36.2) | 36.4 (35.8–37.1) | 34.6 (34.0–35.2) | 46.3 (45.6–46.8) | 50.4 (49.8–51.2) | 5.3 (5.0–5.6) |
| Men | ||||||
| No cardiovascular disease | 34.3 (33.9–34.6) | 28.6 (28.3–28.9) | 32.3 (32.1–32.7) | 24.524.2–24.8) | 27.9 (27.6–28.3) | 1.1 (1.0–1.2) |
| Ischemic heart disease | 42.9 (42.3–43.6) | 27.6 (27.0–28.2) | 31.6 (31.0–32.2) | 71.9 (71.3–72.4) | 37.5 (36.8–38.1) | 6.7 (6.4–7.1) |
| Atrial fibrillation | 40.1 (39.4–40.9) | 28.9 (28.3–29.6) | 31.6 (30.9–32.2) | 72.6 (71.9–73.2) | 48.4 (47.5–49.2) | 9.9 (9.4–10.3) |
| Congestive heart failure | 48.1 (47.1–48.9) | 28.1 (27.3–28.8) | 25.6 (24.8–26.4) | 73.2 (72.4–74.0) | 63.5 (62.5–64.6) | 19.2 (18.5–19.9) |
| Cerebrovascular disease | 40.7 (39.7–41.7) | 25.4 (24.5–26.4) | 35.3 (34.3–36.3) | 47.5 (46.5–48.5) | 37.0 (35.9–38.1) | 5.1 (4.7–5.6) |
| Diabetes mellitus | 46.4 (45.8–46.9) | 32.2 (31.8–32.8) | 38.2 (37.7–38.8) | 46.3 (45.8–46.7) | 43.9 (43.4–44.6) | 5.3 (5.0–5.5) |
Proportions of patients are presented as percentages with 95% confidence intervals, according to comorbidity. Cerebrovascular disease includes transient ischemic attack and stroke. No cardiovascular disease is defined as patients with hypertension with no ischemic heart disease, atrial fibrillation, congestive heart failure, or cerebrovascular disease. Abbreviations: ACEIs, angiotensin‐converting enzyme inhibitors; ARBs, angiotensin receptor blockers; CCBs, calcium channel blockers; MRAs, mineralocorticoid receptor antagonists.
The most common drug combinations were β‐blocker + CCB, β‐blocker + ACEI, ARB + diuretic, and β‐blocker + diuretic in men, and β‐blocker + diuretic, ARB + diuretic, and β‐blocker + CCB in women (Table 1). The fixed combination of ARB + diuretic was more often used than the fixed combination of an ACEI + diuretic (9.5 vs 4.7%, P < .001), and this was more pronounced among patients with diabetes mellitus (data not shown).
The use of combination therapy with more than two drug classes was not common. Thus, 21% of patients received one drug class, 28% received two drug classes, 21% received three drug classes, and 14% received four or more drug classes.
4. DISCUSSION
Treatment of hypertension should aim to reduce total cardiovascular risk, where antihypertensive treatment is one of several components, including lifestyle modification, smoking cessation, lipid lowering, and glycemic control. This large contemporary database of more than 292 000 patients with hypertension in Sweden comprises information on patient characteristics, comorbidity, and the current use of antihypertensive drugs, and provides several important findings. The majority of all patients with hypertension attending health care had their diagnosis of hypertension documented in primary care, and approximately half of the patients were recorded in primary care only. As the majority of patients attend primary care for treatment and follow‐up of hypertension, actions to improve treatment and control of hypertension are best directed to health providers in primary care.
Population studies show that approximately half of all cases of hypertension are undetected.24 We observed a prevalence rate of diagnosed hypertension of 14%. This would suggest an approximately 28% prevalence rate of hypertension in the current study population, in agreement with previous studies.1, 2, 3 The most common comorbidities in men with hypertension were diabetes mellitus, ischemic heart disease, and atrial fibrillation. In women with hypertension, who more seldom had cardiovascular disease than men, the most common comorbidities were diabetes mellitus, asthma/chronic obstructive pulmonary disease, and ischemic heart disease. Swedish national statistics report a higher number of women who are smokers than men, which could at least in part explain the higher prevalence of chronic obstructive pulmonary disease in women.25 Women were also slightly older, which may have contributed to the results. Our findings in a large unselected cohort of patients with hypertension correspond well with other Swedish studies26 and provide us with information on concomitant disease in patients with treated hypertension.
This study reports on dispensed drugs, which give a better reflection of medications actually taken by the patients than information on prescribed drugs, which is often reported by other studies. We found that important sex differences in antihypertensive drug treatment prevail. Women were more often treated with diuretics then men. While the use of ARBs was similar in women and men, ACEIs and CCBs were more common in men. ACEIs more often cause dry cough in women than in men and are often unsuitable in fertile women because of their potential teratogenicity, which could have contributed to these differences. In patients without cardiovascular disease, β‐blocker therapy was more common among women than men. This might be attributable to other concomitant symptoms and conditions (eg, migraine and palpitations) but remains to be examined. Our findings on dispensed antihypertensive drugs are in agreement with other results from Sweden and other countries.27, 28 The results indicate that concomitant cardiovascular disease and diabetes mellitus influence the choice of antihypertensive drug classes, as expected. However, compared with men, fewer women with concomitant diabetes mellitus and with heart failure were taking ACEIs/ARBs. This confirms our previous findings, which also persisted when adjusted for potential confounding factors such as age, sex, cardiovascular comorbidity, psychiatric disorders, educational level, and country of birth.29 Factors such as differences in heart failure comorbidity between women and men could contribute to our findings, and our data do not allow us to differentiate between heart failure with reduced ejection fraction or preserved ejection fraction. Thus, β‐blockers and blockers of the renin angiotensin–aldosterone system are indicated in heart failure with reduced ejection fraction, which is more prevalent in men, whereas heart failure with preserved ejection fraction, which is more common in women, currently has no specific recommended drug treatment.30 In summary, studies suggest similar treatment benefits from different antihypertensive drugs in women and men,9, 10 but our findings confirm prevailing sex differences in antihypertensive treatment. There is room for improvement to achieve more equal treatment between men and women.
The use of three or more antihypertensive drug classes in combination was uncommon. Several patients were taking one (21%) or two (28%) drug classes, and only 34% were taking three or more antihypertensive drugs. This is in agreement with other studies.31, 32 Studies show that many patients with hypertension do not reach target BP.11, 12 Taken together, these results suggest that titration of antihypertensive drug treatment could improve BP control, which would likely reduce cardiovascular complications.
β‐Blocker therapy was common, similar to other studies in Sweden and elsewhere18, 26, 28 This may reflect that β‐blockers were long considered first‐line antihypertensive therapy and changes in prescribing traditions are slow. In addition, cardiovascular comorbidity with compelling indications for β‐blockers such as ischemic heart disease (14%), atrial fibrillation (11%), and heart failure (8%) were common. However, the use of β‐blockers has declined in Sweden, and β‐blockers as a first prescription for patients newly initiated on antihypertensive treatment is much less common.26, 33 Evidence suggests that a combination of an ACEI and an ARB is unfavorable.34, 35 Accordingly, we found only 4% of patients with both an ACEI and an ARB dispensed during the study period. However, our data do not allow us to differentiate between patients actually taking both drugs at the same time and those switching from one class to another during 2013.
Furthermore, our results show the changes in the use of antihypertensive medications with advancing age of the patient. The use of β‐blockers and diuretics increased with age, whereas the use of ACEIs, ARBs, and CCBs decrease with age. This could be explained to some extent by an age‐dependent renal impairment,36 by increased cardiovascular or diabetes mellitus comorbidity26 and by a greater susceptibility to drug‐induced side effects with advancing age. There may also be a cohort effect in that elderly patients have remained on their antihypertensive treatment that was started many years ago when β‐blockers and diuretics were considered first‐line therapy. The use of β‐blockers as first‐line antihypertensive drug treatment has been challenged13 and more recently, some,14, 37 but not all,38 guidelines favor other drug classes than β‐blockers, as β‐blockers may by less effective in reducing BP. CCBs were the second most common antihypertensive drug class in women aged 60 to 79 years and in men aged 60 to 89 years, with approximately 30% to 35% of the patients taking CCBs (Figure 4). However, CCBs are considered particularly effective in the elderly, are not affected by renal function, and may be underused in elderly antihypertensive patients. Of note, very old patients received fewer antihypertensive drugs, although there is evidence in favor of drug therapy in this age group.39, 40
We compared our results with data from the most recent available larger Swedish studies on patients with hypertension, representing different geographic regions (Table 3). HyperQ was a cross‐sectional study (2002–2005) comprising approximately 6500 patients recruited from 264 primary care physician settings intending to describe the usual daily care of treated hypertension in primary care.18 The Swedish Primary Care Cardiovascular Database represents data extraction from electronic medical records in approximately 75 000 unselected patients with hypertension in primary care from 2001–2008, and have reported data for 2007–2008.26 QregPV is a regional administrative database from the Southwest of Sweden reporting information from electronic medical records in approximately 230 000 unselected primary care patients with hypertension.41 Our findings show similar findings concerning basic characteristics such as age, sex, comorbidities, and drug treatment. This suggests that our contemporary results are representative for Sweden. Furthermore, the results presented in Table 3 provide circumstantial support for improved BP control in Sweden over time, as suggested by other reports.26, 41, 42
Table 3.
Comparison of contemporary hypertension cohorts in Sweden
| Current study | HyperQ18 | SPCCD26 | QregPV41 | |
|---|---|---|---|---|
| Year of survey | 2013 | 2002–2005 | 2007–2008 | 2014 |
| Patients, No. | 292 623 | 6537 | 62 407 | 223 663 |
| Men/women, % | 47/53 | 48/52 | 44/56 | 48/53 |
| Age (range), y | 68 ± 13 (20–109) | 66 ± 12– | 69 ± 13 (37–106) | 69 ± 12 (15–113) |
| Systolic/diastolic blood pressure, mm Hg | – | 147 ± 17/82 ± 9 | 143 ± 18/80 ± 10 | 136 ± 16/79 ± 13 |
| Atrial fibrillation/flutter, % | 11 | – | 8 | – |
| Ischemic heart disease, % | 14 | – | 15 | 15 |
| Heart failure, % | 8 | – | 8 | – |
| Diabetes mellitus, % | 21 | 22 | 24 | 22 |
| Cerebrovascular disease, % | 6 | – | 8 | – |
| No cardiovascular disease, % | 59 | – | 56 | – |
| Data on medicines used | Dispensed | Prescribed | Prescribed | Dispensed |
| ACEIs, women, % | 27 | 18 | 32 | 25 |
| ACEIs, men, % | 36 | 27 | 44 | 35 |
| ARBs, women, % | 30 | 34 | 23 | 30 |
| ARBs, men, % | 29 | 35 | 23 | 30 |
| ACEIs and/or ARBs, women, % | 57 | 51 | 55 | 54 |
| ACEIs and/or ARBs, men, % | 65 | 62 | 67 | 64 |
| CCBs, women, % | 29 | 26 | 30 | 32 |
| CCBs, men, % | 34 | 34 | 35 | 31 |
| β‐Blockers, women, % | 39 | 54 | 51 | 41 |
| β‐Blockers, men, % | 38 | 51 | 49 | 39 |
| Diuretics, women, % | 38 | 64 | 48 | 37 |
| Diuretics, men, % | 32 | 48 | 37 | 32 |
Contemporary Swedish cohort studies on patients with hypertension reporting on 10 000 or more patients from 2000 or later. Data are presented as mean values ± standard deviations or proportions, as appropriate. Cerebrovascular disease includes transient ischemic attack and stroke. No cardiovascular disease is defined as patients with hypertension with no ischemic heart disease, atrial fibrillation, congestive heart failure, or cerebrovascular disease. Abbreviations: ACEIs, angiotensin‐converting enzyme inhibitors; ARBs, angiotensin receptor blockers; CCBs, calcium channel blockers; SPCCD, Swedish Primary Care Cardiovascular Database.
5. STUDY STRENGTHS AND LIMITATIONS
There are some strengths to this study. This contemporary database comprises more than 292 000 patients with hypertension and represents real‐life data from unselected patients from care providers in primary and secondary care settings. There was no selection bias in patients or physicians caused by any voluntary participation, as can be seen in other similar studies. We used data extracted from electronic records, not self‐reported questionnaires, including information on dispensed drugs rather than prescribed antihypertensive drugs, which has often been used in previous studies. There are also important limitations to consider. This study captured only patients attending care with a recorded diagnosis of hypertension, and people with unrecognized disease were not included. Of note, the diagnoses of hypertension in patients from some private care providers, representing approximately 20% of all outpatient visits in the Stockholm region, are not available in the healthcare registers.43 However, many of these patients may have attended hospital care or primary care (Figure 2). The diagnoses were set at the discretion of the treating physicians and were not adjudicated. The validity of the Swedish National Patient Registry is high22 but the accuracy of diagnoses in primary care is less well studied. However, much comorbidity will be associated with hospital admissions and this will likely improve diagnostic accuracy. We did not have access to BP recordings in the individual patients, as this information is not available in the administrative health data register of the Stockholm region. Finally, the available information on dispensed drugs does not allow us to differentiate between patients taking combinations of several drugs and those switching from one drug to another within the specific study period.
6. CONCLUSIONS
This large database shows that comorbidity and age is taken into consideration for antihypertensive medications. However, we confirm prevailing sex differences in antihypertensive drug treatment. Few patients receive a combination of three or more antihypertensive drug classes. Thus, there is room for improvement, which could lead to a reduced number of cardiovascular complications.
CONFLICTS OF INTEREST
The authors have no conflicts of interest to disclose.
Wallentin F, Wettermark B, Kahan T. Drug treatment of hypertension in Sweden in relation to sex, age, and comorbidity. J Clin Hypertens. 2018;20:106–114. 10.1111/jch.13149
Funding information
Supported by grants from the Swedish Heart‐Lung Foundation 20130467 and Stockholm County Council (ALF project; 20140348)
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