Question

In Table 3, look at the risk ratio for hospitalization due to supraventricular arrhythmia. Which of the choices below represents the most accurate interpretation?

A. Patients in the Digoxin group were 13% less likely to be hospitalized due to supraventricular arrhythmia compared with patients in the placebo group but the difference was not statistically significant.

B. Patients in the Digoxin group were 87% less likely to be hospitalized due to supraventricular arrhythmia compared with patients in the placebo group but the difference was not statistically significant.

C. Patients in the placebo group were 13% less likely to be hospitalized due to supraventricular arrhythmia compared with patients in the digoxin group but the difference was not statistically significant.

D. More than one answer is correct.

E. None of the above.

TABLE 3. PATIENTs HOSPITALIZED DURING THE STUDY, AcCORDING TO STuDY GROuP AND REASON FOR HoSPITALIZATION DIGOXIN N-3397) PLACEBO 3403) ABSOLUTE DIFFERENCEt RISK RATIO (95% CI) REASON FOR H osPITALIZATION (N P VALUE no. of patients (%) 1694 (49.9)1850 (54.4) 910 (26.8) 1180 (34.7) -4.5 -7.9 0.87 (0.81-0.93) <0.001 0.72 (0.66-0.79) Worsening heart failure Ventricular arrhythmia, cardiac arrest Supraventricular arrhythmiaS <0.001 142 (4.2) 133 (3.9) 14 (0.4) 67 (2.0) 195 (5.7) 145 (4.3) 152 (4.5) 9 (0.3) 31 (0.9) 201 (5.9) 0.1 0.98 (0.78-1.24) -0.6 0.87 (0.69-1.10) 0.1 1.56 (0.68-3.61) Atrioventricular block, bradyarrhythmia Suspected digoxin toxicity Myocardial infarction Unstable angina Stroke Coronary revascularization Cardiac transplantation Other cardiovascular 1.l 2.17 (1.42-3.32) <0.001 0.2 0.97 (0.79-1.18) 399 (11.7) 398(11.7)0 1.01 (0.87-1.16) -0.2 0.95 (0.77-1.19) 0.4 1.17 (0.85-1.61) 0.3 1.57 (0.84-2.94) 2.1 1.20 (1.05-1.38) -0.4 0.94 (0.79-1.12) 14 1.06 (0.98-1.15) 0. 1.11 (0.59-2.10) 157 (4.6) 83 (2.4) 25 (0.7) 164 (4.8) 71 (2.1) 16 (0.5) 452 (13.3 381 (11.2) 1126 (33.1) 1079 (31.7) 2184 (64.3) 2282 (67.1) 238 (7.0) 252 (7.4) Other noncardiac and nonvascular Unspecified No. of patients hospitalized No. of hospitalizations 20 (0.6) 18 (0.5) -2.8 0.92 (0.87-0.98) 0.006 6356 6777 Data shown include the first hospitalization of each patient for each reason. tAbsolute differences were calculated by subtracting the percentage of patients hospitalized in the placebo group from the percentage of patients hospitalized in the digoxin group (before values were rounded). #Risk ratios and confidence intervals (CI) were estimated from a Cox proportional-hazards model that used the first hospitalization of each patient for each reason. SThis category includes atrioventricular block and bradyarrhythmia. TThis category includes coronary-artery bypass grafting and percutaneous transluminal coronary angioplasty This category includes embolism, venous thrombosis, peripheral vascular disease, hypertension, other vascular surgery cardiac catheterization, other types of catheterization, pacemaker implantation, installation of automatic implantable car diac defibrillator, electrophysiologic testing, transplant-related evaluation, nonspecific chest pain, atherosclerotic heart dis- ease, hypotension, orthostatic hypotension, and valve operation.

Answer 1

option A) Patients in the Digoxin group were 13% less likely to be hospitalized due to supraventricular arrhythmia compared with patients in the placebo group but the difference was not statistically significant.   is correct

A risk ratio < 1 suggests a reduced risk in the exposed group

Note that risk ratio = 87%

100 - 87= 13

hence Patients in the Digoxin group were 13% less likely to be hospitalized due to supraventricular arrhythmia compared with patients in the placebo group

since 1 is present in CI (0.69, 1.1)

result is not statistically significant