Uncontrolled and controlled hypertensive patients ()
The proportion of patients with uncontrolled hypertension declined from 73.2% in 1988–1994 to 52.5% in 2005–2008. Men were more likely than women to have uncontrolled hypertension in 1988–1994 and 2005–2008. Across surveys, a lower proportion of Whites and a higher proportion of Blacks and Hispanics of any race were represented among uncontrolled patients. As expected, systolic and diastolic BP values were lower in controlled than uncontrolled patients. Systolic BP did not change over time in either group, whereas diastolic BP declined in both.
The number of BP medications increased over time in both treated uncontrolled and controlled patients but did not differ between groups. Uncontrolled patients were more likely to report 0–1 healthcare visits annually, whereas controlled patients were more likely to report ≥4. The proportion of uninsured patients did not change in controlled hypertensives but increased in uncontrolled patients over time. Body mass index rose over time in both groups and was higher in controlled patients. LDL-cholesterol declined over time in both groups and was lower in controlled patients in 1999–2004 and 2005–2008. The prevalence of diabetes mellitus increased over time and was more common in controlled than uncontrolled patients. The percentage of current cigarette smokers did not differ between controlled and uncontrolled hypertensives but was lower among uncontrolled patients in 1999–2004 than the other two time periods.
The percentage of hypertensive patients with CKD did not change significantly with time and was not different in uncontrolled than controlled patients. Prevalent clinical CVD was more common in controlled than uncontrolled patients in 1988–1994 and 1999–2004 but did not change with time. Framingham ten-year CHD risk was higher in controlled than uncontrolled patients in 1988–1994 and 1999–2004.
Characteristics of uncontrolled and controlled individuals with hypertension in three NHANES time periods.
Antihypertensive medication number
The percentage of all hypertensive individuals that were untreated declined, while the percentage on two and ≥3 BP medications increased over time (). Among all uncontrolled patients, the percentage of untreated subjects declined with time but the mean remained >50% in 2005–2008 (52.2%, 95% confidence interval [CI] 48.1–56.3% [). The percentage of treated uncontrolled patients on 1 medication fell, whereas those on ≥3 medications rose with time (). Among treated uncontrolled [1C] and treated controlled hypertensive patients [1D], the number of BP medications reported and changes over time were similar. The proportion on one BP medication fell, and those on ≥3 BP medications rose. All controlled hypertensives reported taking BP medications. However, ~4–5% of them did not bring any antihypertensive medications to the examination, nor did they identify any BP medications during the interview including ‘unspecified’ ().
Figure 1 The percentages are depicted of hypertensive patients that reported taking 0, 1, 2, and ≥3 antihypertensive medications for (A) all (B) all uncontrolled (C) treated uncontrolled (D) treated controlled patients in the different NHANES. Symbols (more ...)
Uncontrolled hypertensive patients grouped by number of antihypertensive medications ()
The proportion of untreated patients fell between 1988–1994 and 2005–2008, whereas the percentage on 1–2 medications did not change and the percentage on ≥3 medications rose. The proportion of uncontrolled hypertensive patients who were uninsured increased with time. Systolic BP was lower and diastolic BP higher in untreated than treated patients. Untreated hypertensive patients were younger and more likely to be men, infrequent healthcare users, uninsured and to have 10-yr CHD risk <10% than treated patients. Conversely, untreated patients were less likely to have ≥4 healthcare visits annually, Stage 2 hypertension, diabetes mellitus, CKD and 10-yr CHD risk >20% than treated patients, especially those on ≥3 BP medications, i.e., apparent treatment resistant hypertension (aTRH).
Characteristics of uncontrolled hypertensive patients grouped by number of antihypertensive medications reportedly taken.
Controlled hypertensive patients grouped by number of antihypertensive medications ()
In general, there were more differences by number of medications within uncontrolled than within controlled hypertensive patients. While all controlled hypertensive patients reported taking BP medication, 4–5% across all survey periods did not verbally identify or physically bring any of them during their assessment. Untreated hypertensive patients were younger than those on ≥3 medications. Framingham 10-yr CHD risk generally increased with the number of medications with significant differences in 1999–2004 and 2005–2008. The percentage of controlled hypertensive patients on ≥4 medications was 2.3% [1.3%–3.3%] in 1988–1994, 5.2% [3.6%–6.8%] in 1999–2004, and 7.3% [5.1%–9.4%] in 2005–2008
Characteristics of controlled hypertensive patients grouped by number of antihypertensive medications reportedly taken.
Therapeutic inertia in uncontrolled hypertensive patients with ≥2 healthcare visits annually ()
Using the definition provided in Methods, the percentage of patients with no therapeutic inertia rose with time over the three NHANES periods, whereas the percentage of patients with high level therapeutic inertia declined. Nevertheless, more than half of uncontrolled hypertensive patients in all time periods had a moderate or high level of therapeutic inertia.
Therapeutic inertia among uncontrolled hypertensive patients in three NHANES survey periods.
Classes of antihypertensive medications ()
The class of antihypertensive medications reported by controlled and uncontrolled hypertensive patients taking 1, 2 and ≥3 such medications is provided for each of the three NHANES periods. The NHANES databases do not indicate the order antihypertensive agents were added for patients that reported taking 2 and ≥3 BP medications. In all time periods, ACE inhibitors, beta-blockers and CCBs were the agents most often reported by controlled and uncontrolled hypertensive patients reportedly taking a single antihypertensive medication. Diuretics, especially thiazide-type diuretics, showed the largest increase in percentage utilization as BP medication number rose from one to three or more. There were a limited number of differences significant at p<0.01 level between uncontrolled and controlled hypertensive patients that reported taking each class of medication in the three NHANES time periods. Non-dihydropyridine calcium antagonists were the class of antihypertensive medication class with the largest number of significant differences between controlled and uncontrolled patients and were taken more often by those who were uncontrolled.
Antihypertensive medication classes prescribed to controlled and uncontrolled hypertensive patients by medication number.
Untreated hypertension ()
By multivariable logistic regression, the clinical variables consistently and independently associated with untreated hypertension across the three NHANES periods included male sex, patients with 0–1 healthcare visits/yr, BMI <25 kg/m2, Stage <3 CKD, and 10-year FCR 10–19% and <10% compared to the reference groups.
Figure 2 The independent relationship between selected clinical variables and the dependent variable untreated hypertension are shown as multivariable odds ratios and 95% confidence intervals for each of the three NHANES periods. The reference group for comparison (more ...)
Uncontrolled hypertension on 1–2 BP medications ()
All of the independent variables shown in and were examined simultaneously in multivariables logistic regression analysis. The clinical variables independently associated with uncontrolled hypertension on 1–2 BP medications included male sex (1999–2004, 2005–2008), black race (1988–1994, 1999–2004), age and 10-year CHD risk >20% (all time periods). Patients on thiazide-type diuretics (1988–1994, 1999–2004) and angiotensin converting enzyme (ACE) inhibitors and/or angiotensin receptor blockers (1999–2004, 2005–2008) were less likely to have hypertension uncontrolled on 1–2 BP medications. In contrast, patients reportedly taking non-dihyrdropyridine calcium channel blockers (CCBs) were more likely to have treated, uncontrolled hypertension (1988–1994, 2005–2008).
Figure 4 The independent relationship between selected clinical variables and the dependent variable apparent treatement resistant hypertension (aTRH, [uncontrolled on ≥3 BP medications]) are shown as multivariable odds ratios and 95% confidence intervals (more ...)
Figure 3 The independent relationship between selected clinical variables including class of antihypertensive medications and the dependent variable uncontrolled hypertension on 1–2 antihypertensive medications are shown as multivariable odds ratios and (more ...)
Clinical factors independently associated with aTRH among all uncontrolled patients ()
In all time periods, patients reporting ≥4 healthcare visits annually were more likely to have aTRH, i.e.,uncontrolled on ≥3 BP medications. Other clinical factors consistently and independently associated with aTRH in multivariable logistic regression included obesity, CKD and 10-year CHD risk >20%. Increasing age and black race were independently linked with aTRH in 2005–2008, and patients with 10-yr CHD risk 10–20% were more likely to have TRH in 1988–1994 and 1999–2004.
No significant differences were seen in the percentages of controlled and uncontrolled hypertensive patients taking various classes of antihypertensive medications in 2005–2008 with one exception (). Non-dihyrdropyridine calcium channel blockers were taken more often by uncontrolled than controlled hypertensive patients.
Figure 5 The percentage of controlled and uncontrolled hypertensive patients taking various classes of antihypertensive medications are depicted for NHANES 2005–2008 only. The percentages of patients within each bar are further subdivided by those who (more ...)