Drug prescriptions unadapted to the renal function in patients aged 80 years and older

Figures & data

Table 1. Baseline characteristics of whole BELFRAIL study population (n = 539) and the study population divided into three categories based on the eGFR of the participants (percentages).

	eGFR (MDRD equation)
n %	All participants (n = 539)	> 50 ml/min/1.73 m^2 (n = 397)	30–50 ml/min/1.73m^2 (n = 111)	< 30 ml/min/1.73m^2 (n = 31)	P for trend
≥ 85 years	41	38	46	59	< 0.01
Male	37	28	33	45	0.45
Reported hypertension	71	68	78	84	0.07
Diabetes mellitus	19	17	22	36	0.10
Myocardial infarction in history	11	11	14	10	0.85
Cerebrovascular event in history	9	9	6	7	0.53
Peripheral arterial disease in history	9	7	12	16	0.05
Reported osteoarthritis	5	4	7	3	0.17
Reported arthrosis	58	55	66	67	0.19
Reported arrhythmia	11	13	11	16	0.72
Chronic atrial fibrillation	9	9	11	12	0.54
Reported peripheral oedema	34	32	39	42	0.15
History of decompensated heart failure	11	7	21	29	< 0.01

Table 2. Overall drug use in the BELFRAIL population (n = 539) by ATC classification.

	eGFR 4 (MDRD equation)
ATC classification	All participants (n = 539)	> 50ml/min/1.73 m² (n = 397)	30–50ml/ min/1.73 m² (n = 111)	< 30ml/min/1.73 m² (n = 31)	P
Alimentary tract and metabolism	50%	46%	64%	65%	< 0.01
Blood and blood forming organs	55%	52%	59%	61%	0.37
Cardiovascular system
0 drugs	14%	17%	6%	7%	< 0.01
1 drug	23%	25%	20%	10%
2 different drugs	31%	31%	28%	32%
≥ 3 different drugs	32%	28%	46%	52%
Musculo-skeletal system	14%	14%	18%	19%	0.39
Nervous system	34%	35%	39%	39%	0.76
Respiratory system	5%	6%	5%	7%	0.97

Table 3. Intake and mean DDD of drugs requiring adaptation to the renal function in the BELFRAIL study population (n = 539).

	eGFR 4 variable MDRD equation
	All participants (n = 539)	> 50ml/min/1.73 m^2 (n = 397)	30–50 ml/min/1.73 m^2 (n = 111)	< 30ml/min/1.73 m^2 (n = 31)	P
Metformin	46 (9%)	31 (8%)	13 (12%)	2 (7%)	0.45
Mean DDD metformin (min–max)	1259	1243 (425–2550)	1320 (500–2550)	1063 (850–1275)	0.83
Gliclazide	15 (3%)	7 (2%)	7 (6%)	1 (3%)	0.04
Mean DDD gliclazide (min–max)	72.5	63 (30–160)	86 (15–320)	30 (30)	0.79
Tramadol	34 (7%)	25 (6%)	8 (7%)	1 (3%)	0.77
Mean DDD tramadol (min–max)	106	109 (15–300)	102 (8–300)	100 (50–150)	0.95
Spironolactone	22 (4%)	12 (3%)	10 (9%)	0	0.01
Mean DDD spironolactone (min–max)	1.71	54 (25–200)	27 (12–50)	No cases	0.14
Sotalol	17 (3%)	14 (4%)	2 (2%)	1 (3%)	0.63
Mean DDD sotalol (min–max)	113	120 (40–160)	80 (80)	80 (80)	0.44
Atenolol	30 (6%)	22 (6%)	6 (5%)	2 (7%)	0.96
Mean DDD atenolol (min–max)	59.2	63 (25–150)	67 (50–100)	63 (25–100)	0.83
Ranitidine	35 (7%)	24 (6%)	8 (7%)	3 (10%)	0.69
Mean DDD ranitidine (min–max)	262	269 (150–300)	244 (150–300)	300 (300)	0.25
Allopurinol	37 (7%)	21 (6%)	10 (9%)	6 (21%)	0.01
Mean DDD allopurinol (min–max)	250	260 (100–300)	260 (100–300)	200 (100–300)	0.29

Table 4. Frequency of the drug use or inappropriate daily doses based on the renal function in the BELFRAIL cohort (n = 539).

	eGFR (MDRD) (ml/min/1.73 m²)	Possible effect(s)	Participants with inappropriate drug use
Metformine (n = 46)	30–50	Increased risk for lactate acidosis	13
	< 30	Strongly increased risk for lactate acidosis	2
Gliclazide (n = 15)	< 50	Increased risk for hypoglycaemia	8
Tramadol (n = 34)	< 30	More side-effects when DD > 200 mg/d	0
Spironolactone (n = 22)	< 50	Increased risk for hyperkalaemia	10
Sotalol (n = 17)	30–50	More side effects when DD > 160 mg/d	0
	< 30	More side effects when DD > 80 mg/d	0
Atenolol (n = 30)	< 30	More side effects	2
Ranitidine (n = 35)	< 30	More side effects	3
Allopurinol (n = 37)	30–50	More toxic side effects when DD > 200 mg	8
	< 30	More toxic side effects when DD > 100 mg	3

Table 5. Chance of receiving an inappropriate drug or inappropriate daily dose based on renal function.

Drug with low eGFR contra-indication	eGFR (ml/ min/ 1.73 m²)	Adjusted^a OR (CI) for receiving drug
Metformine	> 50 ml/min	1 (ref)
	30–50 ml/min	1.58 (0.77–3.24)
	< 30 ml/min	0.76 (0.16–3.51)
Gliclazide	> 50 ml/min	1 (ref)
	< 50 ml/min	4.51 (1.45–14.02)
Spironolactone	> 50 ml/min	1 (ref)
	< 50 ml/min	1.87 (0.74–4.71)
Atenolol	> 30 ml/min	1 (ref)
	< 30 ml/min	1.53 (0.33–7.05)
Ranitidine	> 30 ml/min	1 (ref)
	< 30 ml/min	2.00 (0.53–7.53)
Drug with maximum DDD when eGFR low	eGFR (ml/min/1.73 m²)	Adjusted^a OR (CI) for receiving higher dose
Tramadol (DD > 200 mg)	> 50 ml/min	No cases in low eGFR group
	< 50 ml/min
Sotalol (DD > 160 mg)	> 50 ml/min	No cases in low eGFR group
	< 50 ml/min
Sotalol (DD > 80 mg)	> 30 ml/min	No cases in low eGFR group
	< 30 ml/min
Allopurinol (DD > 200 mg)	> 50 ml/min	1 (ref)
	< 50 ml/min	1.67 (0.75–3.75)
Allopurinol (DD > 100 mg)	> 30 ml/min	1 (ref)
	< 30 ml/min	3.48 (1.26–9.61)

^aAdjusted for age and comorbidities reported by the GP who are related to the eGFR (Table 1): reported hypertension, peripheral arterial disease in history episode of decompensated heart failure and diabetes mellitus.