An echo to Choosing Wisely^® in Switzerland

Figures & data

Table 1 Population characteristics

Characteristics	All patients (n = 2023)	Patients before implementation (n = 997, 49.3%)	Patients after implementation (n = 1026, 50.7%)	P
Demographics
Age, median (IQR)	71 (55–82)	72 (54–82)	71 (55–82)	0.54a
Gender (female), n (%)	1007 (49.8)	484 (48.5)	523 (51)	0.29b
Clinical features
Hospitalization days, median (IQR)	6 (3–10)	6 (4–11)	6 (3–10)	0.06a

Notes:

a P-value calculated using Mann–Whitney U test.

b P-value calculated using Wald Chi-square test.

Abbreviation: IQR, interquartile range.

Figure 1 Number of blood draws per hospitalization.

Notes: The histogram shows how the blood draws per hospitalization were distributed across the two patient groups, before (light gray) and after (dark gray) implementation of the “Smarter Medicine” recommendation. There is a significant decrease in the number of blood draws after recommendation implementation; P = 0.002 (Mann–Whitney U test).

Table 2 Outcomes of “Smarter Medicine” recommendation implementation

	Patients before implementation (n = 997, 49.3%)	Patients after implementation (n = 1026, 50.7%)	P
Blood draws
Median per patient (IQR)	4 (2–7)	4 (2–6)	0.002a
Patients with four or less blood withdrawals, n (%)	540 (54)	625 (61)
Patients with more than four blood withdrawals, n (%)	457 (46)	401 (39)
Blood volume (mL)
Median per patient (IQR)	65 (28–108)	56 (27–99)	0.01a

Note:

a P-value calculated using Mann-Whitney U Test.

Abbreviation: IQR, interquartile range.

Figure 2 Distribution of blood volume drawn per hospitalizations.

Notes: The box plot represents the volume of blood drawn per hospitalization before (light gray) and after (dark gray) implementation of the “Smarter Medicine” recommendation. *Significant difference before and after implementation; P = 0.01 (Mann–Whitney U test). Values above 250 mL are not shown.

Table S1 Number of blood tubes drawn and volume of blood drawn according to the type of blood tubes

	All patients (n = 2023)	Patients before implementation (n = 997, 49.3%)	Patients after implementation (n = 1026, 50.7%)
Number of blood tubes drawn (median, mean per patient)
Total	36,449 (12, 18)	18,685 (14, 19)	17,764 (12, 17)
Serum chemistry	10,430 (4, 5)	5344 (4, 5)	5086 (3, 5)
Ethylenediaminetetraacetic acid	10,404 (3, 5)	5419 (4, 5)	4985 (3, 5)
Citrate	8217 (2, 4)	4283 (2, 4)	3934 (2, 4)
Heparin	2164 (1, 1)	1051 (1, 1)	1113 (1, 1)
Blood culture	4344 (0, 2)	2154 (0, 2)	2190 (0, 2)
Immunohematology	801 (0, 0)	380 (0, 0)	421 (0, 0)
Serology	17 (0, 0)	11 (0, 0)	6 (0, 0)
Erythrocyte sedimentation rate	72 (0, 0)	43 (0, 0)	29 (0, 0)
Volume of blood drawn according to blood tubes (mL) (median, mean)
Total	169368 (60, 84)	85,337 (65, 86)	82,120 (56, 81)
Serum chemistry (5 mLa)	52,150 (20, 26)	26,720 (20, 27)	25,430 (15, 25)
Ethylenediaminetetraacetic acid (3 mL)	31,212 (9, 15)	16,257 (12, 16)	14,955 (9, 15)
Citrate (3.5 mL)	28,760 (7, 14)	14,991 (7, 15)	13,769 (7, 13)
Heparin (4 mL)	8656 (4, 4)	4204 (4, 4)	4452 (4, 4)
Blood culture (10 mL)	43,440 (0, 21)	21,540 (0, 22)	21,900 (0, 21)
Immunohematology (6 mL)	4806 (0, 2)	2280 (0, 2)	2526 (0, 2)
Serology (5 mL)	85 (0, 0)	55 (0, 0)	30 (0, 0)
Erythrocyte sedimentation rate (3.6 mL)	259 (0, 0)	155 (0, 0)	104 (0, 0)

Note:

a Requested volume of blood per tube.