Kuramoto 1981.

Methods	Placebo‐controlled single site study conducted in ambulatory patients in home for the aged in Tokyo, Japan. Allocation of individuals within matched pairs to treatment and control groups was made by a blinded statistical coordinator, thought to be randomised but not entirely clear. (Unpublished information as per personal conversation with author as stated in Mulrow 1998 review.
Participants	91 participants (45% female); age range: > 60, mean: 76.1 years, race: not stated The inclusion criteria were SBP/DBP 160/90 mmHg to < 200/110 mmHg Pre‐existing factors: not reported. Blood pressure (BP) entry criteria: not clearly stated Mean blood pressure at entry: 169/86 mmHg (isolated systolic hypertension in 44% of subjects) Pulse pressure was 83 mmHg. Exclusion criteria were not mentioned. Patients were excluded from the trial "when the blood pressure exceeded 200/110, and appearance of cerebrovascular or cardiac complications, other diseases which needed hospital admission, death or moving out from the home were considered to be dropouts." Follow‐up: 2.7 years
Interventions	Treatment: trichlormethiazide 1 mg to 4 mg, 80% monotherapy. Reserpine (0.3 mg), methyldopa (125 mg to 500 mg) and hydralazine (50 mg to 100 mg) added as stepped care approach when needed. Control: placebo
Outcomes	Mortality, stroke, CHD, CHF, systolic BP and diastolic BP Dropout due to side effects: not reported Quality of life or functional status outcomes: not reported
Notes	Difference in blood pressure at study end (based on only 29 patients; Treatment ‐ Control) systolic/diastolic: 0.8/1.3 mmHg Reporting of study methods was inadequate in the publication. We have used unpublished information as per conversation with the study author as stated in the Mulrow 1998 review to assess the risk of bias of this study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"The matched pair group was selected by the age, sex, and blood pressure levels during the drug‐off control period of about 1 year." Comment: method of randomization not described. However, the study reports that "Forty four drug treated cases and 47 placebo treated cases were comparable in blood pressure as well as in laboratory data".
Allocation concealment (selection bias)	Low risk	Allocation of individuals within matched pairs to treatment and control groups was made by a blinded statistical co‐ordinator; thought to be randomized, but not entirely clear (unpublished information as per personal conversation with author by Mulrow 1998).
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Study does not state whether patients and physicians were blinded. Comment: Patient and providers were blinded (unpublished information as per personal conversation with author by Mulrow 1998).
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome assessors were not blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "Patients were excluded from the trial when the blood pressure exceeded 200/110 and appearance of cerebrovascular or cardiac complications, other diseases which needed hospital admission, death, or moving out from home were considered to be drop out." "As a whole, 9 out of 41 cases or 22.0% in the placebo group, and 4 out of 38 cases or 10.5% in the drug group dropped out by cerebrovascular or cardiac complications. In addition to the cerebrovascular and cardiac complications, dropouts due to blood pressure elevation were observed in 8 cases in the placebo group, and total dropouts in the placebo group were 17 cases or 41.5%. This incidence was significantly higher than that in the drug treated group (Table IV)." "Six cases of dropout due to moving out from the home were observed in both groups, and follow‐up cases were 38 in the drug group and 41 in the placebo group." For blood pressure measurements, the number of he follow‐up cases in the placebo group decreased markedly from 47 to 32, 24, 13, and 7 at the end of each year. The number of the follow‐up cases at the end of each year in the drug group declined from 44 to 32, 26, 25, and 22 due to dropouts. Comment: follow‐up of patients was incomplete.
Selective reporting (reporting bias)	Unclear risk	Protocol was not available. Insufficient information to judge selective reporting bias.
Other bias	Unclear risk	Comment: no mention about statistical methods, source of funding, members/team involved in the conduct of trial and conflict of interest.