Nelson MR, Reid CM, Krum H, et al. Predictors of normotension on withdrawal of antihypertensive drugs in elderly patients: Prospective study in second Australian national blood pressure study cohort. British Medical Journal 2002;325:815-17.
PubMed link: https://www.ncbi.nlm.nih.gov/pubmed/12376444
Full text article: https://www.bmj.com/content/325/7368/815.long
Nelson MR, Reid CM, Krum H, et al. Short-term predictors of maintenance of normotension after withdrawal of antihypertensive drugs in the Second Australian National Blood Pressure Study (ANBP2). American Journal of Hypertension 2003;16(1):39-45.
PubMed link: https://www.ncbi.nlm.nih.gov/pubmed/12517681
Full text article: https://academic.oup.com/ajh/article/16/1/39/111225
| Methods | Study design:
· Nelson 2002: Case-control study · Nelson 2003: Before-and-after study Number of groups: Two groups |
| Participants | Number of participants: 503 enrolled, 409 completed (Nelson 2002)
· Maintain normotension group: 181 participants · Return to hypertension: 273 participants o Return to hypertension within 70 days: 135 participants* o Return to hypertension after 70 days: 138 participants* Number of participants: 6291 participants (Nelson 2003) · Maintain normotension group: o Blood pressure remained ≥ 160 mm Hg systolic and ≥ 90 mm Hg diastolic: 1228 participants o Blood pressure remained ≥ 140 mm Hg Systolic and ≥ 90 mm Hg diastolic: 640 participants · Return to hypertension group: o Blood pressure remained < 160 mm Hg systolic or < 90 mm Hg diastolic: 5063 participants o Blood pressure remained < 140 mm Hg Systolic or < 90 mm Hg diastolic: 5651 participants Age: Median 70.0 years (range 65 to 84 years) Sex: 256 female, 198 male (baseline characteristics for male/female add up to 454) Participants with dementia: No (exclusion criteria) Inclusion criteria: · Patients of either sex · 65-84 years of age · Have average untreated sitting systolic blood pressure during the · Screening phase of the study > 160 mm Hg and/or diastolic blood pressure > 90 mm Hg · No history of recent cardiovascular morbidity, serious intercurrent illness or an absolute contraindication to an ACE-inhibitor or a diuretic · Capable of and willing to give informed consent to participation Exclusion criteria: · Stroke or myocardial infarction within the previous six months · Cardiac failure · Dementia · Accelerated or malignant hypertension · Significant renal impairment (plasma creatinine concentration > 0.2mg/l) · Presence of any absolute contraindication to an ACE-inhibitor · Consideration that the patient is unsuitable for the study · Other life-threatening illness · Diuretic Country: Australia Setting: Community – 169 general practices in Victoria, Australia |
| Interventions | Medicine: Antihypertensive
Withdrawal schedule: step-wise withdrawal (i.e., one drug at a time, half doses at weekly intervals to the lowest usual therapeutic dose then cease, and withdrawal |
| Outcomes | Remaining normotensive
Characteristics predictive of remaining normotensive |
| Dates | Dates: Start early 1995
Follow-up duration: 12 months |
| Funding sources | Victorian Health Promotion Foundation, a Victorian state government independent authority |
| Notes | Authors stated: “Competing interests: JJMcN has held other research grants from Vichealth.”
*Indicates the groups that were combined for the purpose of the analysis |
Risk of bias table
| Bias | Authors’ judgment | Support for judgment |
| Random sequence generation (selection bias) | High risk | Observational study |
| Allocation concealment (selection bias) | High risk | Not done |
| Blinding of participants and personnel (performance bias) | 5 out of 5 | The study was not blinded |
| Blinding of outcome assessment (detection bias) | 5 out of 5 | The study was not blinded |
| Incomplete outcome data (attrition bias) | 1 out of 5 | It does not appear that there was missing outcome data. |
| Selective reporting (reporting bias) | 2 out of 5 | It does not appear that there was selective outcome reporting.
The only outcome stated was changes in BP, which was fully reported. There was a protocol published in 1997, which was after the first patient was recruited in 1995. This study was not listed in the protocol as an intended substudy. |
| Confounding (non-randomized) | 5 out of 5 | No concurrent control group |
| Other bias | High risk | ANBP2 received funding from Merck, Sharpand Dohme Pty. Ltd |
| Newcastle-Ottawa scale | ||
| Selection bias | Is the case definition adequate? | Yes |
| Representativeness of the exposed cohort | Truly representative of the average older adult in the community with mild to moderate hypertension – group well described
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| Selection of the non-exposed cohort | Community controls | |
| Definition of Controls | No history of disease (end-point) i.e. remained normotensive | |
| Comparability bias | Comparability of cohorts on the basis of the design or analysis | The study controlled for antihypertensive treatment withdrawal. |
| Outcome bias | Assessment of outcome | Secure record |
| Same method of ascertainment for cases and controls | Yes | |
| Non-Response rate | Same for both groups | |
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