Which drugs cause treatment-related problems? Analysis of 10,672 problems within the outpatient setting

Figures & data

Table 1 Demographic, social, and clinical characteristics of the patient recruited

Variables	%
Age
<18 years old	1.1
18–64 years	68.3
>65 years old	30.6
Missing	0.2
Sex
Male	41.2
Female	58.5
Missing	0.4
Educational level
Illiterate	16.3
Primary	29.3
Secondary	29.0
Tertiary	25.3
Missing	0.1
Health insurance
Insured	96.5
Uninsured	3.3
Missing	0.2
Problem in adherence to medications
Yes	9.1
No	90.9
Missing	0.0
Problem in illness knowledge
Yes	48.7
No	51.3
Nonadherence to self-care and nonpharmacological recommendations
Yes	86.8
No	13.2
Missing	0.9

Table 2 Frequency of drug groups (BNF drug class) causing any TRPs

Drugs	%	n (total 10,672)
Cardiovascular drugs	53	5,656
Endocrine drugs	18.1	1,932
Respiratory drugs	11.4	1,217
Gastrointestinal drugs	7.7	822
Blood and nutrition	4.7	502
Musculoskeletal drugs	1.9	203
Nervous drugs	1.6	171
All medications	1	107
Infection	0.2	21
Genitourinary drugs	0.2	21
Malignancy and immunosuppressant drugs	0.2	21

Abbreviations: BNF, British National Formulary; TRPs, treatment-related problems.

Table 3 Most common drugs causing any TRPs

Drugs	%	n (total 10,672)
Atorvastatin	12.5	1,334
Metformin	8.5	907
Simvastatin	6.2	662
Enalapril	5.9	630
Isosorbide dinitrate	4.6	491
Albuterol (salbutamol)	4.6	491
Aspirin	4.5	480
Lansoprazole	4.2	448
Insulin (any)	4.0	427
Furosemide	2.4	256

Abbreviation: TRPs, treatment-related problems.

Table 4 Drug categories implicated with individual TRPs

TRPs	n	BNF drug class (%)
		GI	CVS	Respiratory	CNS	Infection	Endocrine	GUS	Malignant	Blood and nutrition	Musculoskeletal	All drugs
Drug without an indication	789	70.5	7.0	2.3	3.4	1.3	0.6	0.0	0.0	12.5	2.4	0.0
Addiction or recreational drug use	20	5.0	35.0	0.0	40.0	0.0	5.0	0.0	0.0	15.0	0.0	0.0
The patient treatment should be stepped down	289	22.5	37.0	11.8	0.3	0.0	17.0	0.0	0.0	10.4	1.0	0.0
Duplication	96	1.0	57.3	27.1	1.0	0.0	6.3	3.1	0.0	4.2	0.0	0.0
Avoidable adverse reaction	3	0.0	66.7	0.0	0.0	0.0	33.3	0.0	0.0	0.0	0.0	0.0
Untreated condition	526	0.6	58.0	0.8	4.7	0.2	16.0	0.0	0.2	17.7	3.2	0.0
More effective drug is available	426	0.5	77.2	3.1	5.4	0.2	12.7	0.0	0.0	0.9	0.7	0.0
The patient requires additional/combinational therapy	2,374	0.4	55.7	4.3	11.9	0.0	33.3	0.0	0.2	3.0	0.8	0.0
Dosage regimen issue	513	0.6	56.7	13.8	0.2	0.2	25.3	0.0	0.0	2.5	0.4	0.0
Efficacy interaction issue	40	60.0	30.0	0.0	0.0	0.0	5.0	0.0	0.0	2.5	2.5	0.0
A current drug is contraindicated unsafe for patient condition	74	1.4	24.3	0.0	2.7	0.0	55.4	0.0	0.0	1.4	14.9	0.0
A safer drug is recommended	51	2.0	56.9	0.0	7.8	0.0	15.7	2.0	0.0	0.0	15.7	0.0
The patient is at high risk of developing ADRs	42	0.0	64.3	2.4	4.8	0.0	14.3	0.0	9.5	4.8	0	0.0
Allergic reaction or an undesirable effects	26	0.0	88.5	0.0	0.0	0.0	11.5	0.0	0.0	0.0	0.0	0.0
Safety dosage regimen issues	54	7.4	55.6	9.3	1.9	0.0	14.8	0.0	0.0	7.4	3.7	0.0
Safety interaction issues	77	0.0	81.8	0.0	14.3	0.0	1.3	1.3	0.0	0.0	1.3	0.0
The patient is not instructed or does not understand important information regarding his medications	3,148	3.2	47.3	25.7	1.6	0.2	16.8	0.4	0.3	3.3	1.2	0.0
A problem in patient’s adherence to medications	211	0.0	20.4	16.1	0.0	0.0	11.8	0.0	0.5	1.4	0.9	48.8
Drug product not available	142	0.0	87.3	0.7	0.0	0.0	8.5	0.0	1.4	1.4	0.0	0.0
A need for additional or more frequent monitoring	1,726	0.1	78.0	1.0	0.2	0.0	13.8	0.0	0.2	2.5	4.3	0.0
A need for additional diagnostic test	16	0.0	37.5	0.0	0.0	0.0	12.5	0.0	0.0	50.0	0.0	0.0
A need for consultation	26	26.9	34.6	0.0	19.2	0.0	3.9	0.0	0.0	15.4	0.0	0.0
The chosen medications are not cost-effective	3	33.3	66.7	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Abbreviations: ADR, adverse drug reaction; BNF, British National Formulary; CNS, central nervous system; CVS, cardiovascular system; GI, gastrointestinal; GUS, genitourinary system; TRPs, treatment-related problems.

Table 5 Linked disease with individual TRPs

TRPs	Linked disease (%)
	HTN	DM	IHD	Dyslipidemia	HF	Hyperthyroidism	Hypothyroidism	Renal disease	Hepatic disease	Asthma	COPD	RA	Gout	Dep	Others
Drug without an indication	0.5	1.3	1.3	1.3	0.0	0.0	0.0	0.8	0.0	1.6	0.8	0.3	0.0	0.0	92.1
Addiction or recreational drug use	0.0	0.0	50.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	50.0
The patient treatment should be stepped down	8.2	10.0	13.8	2.2	9.3	0.4	3.7	1.1	0.0	12.6	0.4	1.5	0.7	0.0	36.1
Duplication	39.2	4.1	5.2	10.3	2.1	0.0	0.0	0.0	0.0	24.7	3.1	0.0	0.0	0.0	11.3
Avoidable adverse reaction	66.7	33.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Untreated condition	4.7	13.4	11.7	33.4	0.9	0.3	3.0	5.2	0.0	0.5	0.0	0.3	2.6	0.2	23.7
More effective drug is available	41.9	16.5	16.3	8.2	6.8	0.0	0.0	0.6	0.0	2.3	1.5	0.0	0.0	0.0	5.9
The patient requires additional combination therapy or stepping up	14.3	31.6	20.3	14.7	4.3	0.0	0.5	0.5	0.1	7.4	1.4	0.2	0.5	0.0	4.1
Dosage regimen issue	16.9	24.7	4.5	32.2	0.8	0.0	1.4	0.4	0.0	8.5	5.8	0.2	0.4	0.0	4.3
A current drug is contraindicated unsafe for patient condition	23.4	31.2	2.6	2.6	14.3	0.0	0.0	13.0	0.0	1.3	0.0	0.0	0.0	0.0	11.7
A safer drug is recommended	37.7	22.6	3.8	5.7	1.9	0.0	0.0	1.9	0.0	1.9	0.0	0.0	0.0	0.0	24.5
The patient is at high risk of developing ADRs	29.5	9.1	9.1	9.1	6.8	0.0	0.0	2.3	0.0	2.3	0.0	13.6	2.3	2.3	13.6
Allergic reaction or an undesirable effects	60.0	12.0	0.0	12.0	0.0	0.0	4.0	0.0	0.0	0.0	0.0	4.0	0.0	0.0	8.0
Safety dosage regimen issues	22.9	14.5	3.1	40.5	0.8	0.0	0.0	2.3	0.0	4.6	0.0	0.8	0.0	0.0	10.7
The patient is not instructed or does not understand	31.3	34.4	6.1	7.3	2.0	0.0	0.7	0.4	0.0	10.0	3.6	0.3	0.3	0.0	3.8
A problem in patient’s adherence to medications	25.1	20.2	8.3	12.0	2.3	0.0	1.1	0.0	0.0	15.2	7.1	0.9	1.4	0.0	6.4
Drug product not available	44.9	34.3	6.1	7.7	1.6	0.0	0.1	0.1	0.0	0.9	0.3	0.1	0.0	0.0	3.8
A need for additional or more frequent monitoring	21.0	61.3	0.7	10.9	1.0	0.1	0.7	1.1	0.0	0.9	0.3	0.1	0.6	0.0	1.3
A need for additional diagnostic test	9.9	34.4	0.3	38.0	0.5	0.3	0.8	4.3	0.0	0.0	0.0	0.3	0.0	0.0	11.2
A need for consultation	0.0	79.8	0.7	0.2	0.0	0.0	0.5	9.5	0.0	0.0	0.0	0.8	0.0	0.2	8.3
The chosen medications are not cost-effective	18.2	81.8	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Abbreviations: ADR, adverse drug reaction; Dep, depression; DM, diabetes mellitus; HF, heart failure; HTN, hypertension; IHD, ischemic heart disease; RA, rheumatoid arthritis; TRPs, treatment-related problems.