https://links.lww.com/SLA/D326

Supplemental Figure 1:Precision Calculations

xmin = minimum POMR*

xmax = maximum POMR**

xtrue = true population POMR

*For error calculated using the 95% CI, this represents the upper bound of the CI

** For error calculated using the 95% CI, this represents the lower bound of the CI Absolute Error – EA

E_A=

|

^xmin−x_true

|

⁺

|

^xmax−x_true

|

2

Relative Error – ER (%)

E_R= E´_A x_truex100

B.

A.

D.

C.

Supplemental Figure 2: Precision of100 simulated studies, at 40 different sample sizes for artificial datasets representing populations with (A) 2.5% (B) 5% (C) 15%

and (D) 25% POMR. Dotted line represents true POMR Rate

Supplemental Figure 3: Perioperative mortality rate stratified by month. χ² test of

independence showed no statistically significant association between month and mortality, p = 0.430.

B.

C.

A.

Supplemental Figure 4: Range of POMR for 100 simulated studies, at 40 different sample sizes for (A) all cases at Mulago National Referral Hospital (B) the 10 most common diagnoses and (C) all other diagnoses. Dotted line represents true POMR Rate