Prevalence and outcome of isoniazid-monoresistant tuberculosis at a university hospital in Saudi Arabia

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Figure 1
- *Samples collected from 1st of May 2015 to 30th of April 2019. INH: isoniazid, TB: tuberculosis

Table 1

- Key definitions.

Terms	Definitions
Cured	Patient with lab confirmed TB diagnosis with a negative smear or culture result in the last month of treatment with at least one more previous negative result.¹⁶
Treatment completion	TB patient who completed their treatment without any indications or tests suggesting failure.¹⁷
Treatment success	Patient with TB who met the criteria for “cured” or “treatment completion”.¹⁶
Treatment failure	TB patient with positive smear or culture after 5 months of treatment.¹⁶
Death	TB patient who died during his treatment for any reason.¹⁶
Relapse	Patients who were treated and labeled as “cured” or “treatment completed”, and now present with a diagnosis of TB either relapsed or reinfected.¹⁶
Previously treated	Patient with TB who has received any anti-TB medication.
Treatment unsuccess	Those who fulfill the following definitions: “treatment failure”, “death”, or “relapse”
Loss to follow-up	Patients with an interrupted course of treatment for at least two months.¹⁶
Monodrug resistance	Resistance to a single TB medication only.¹⁶
MDR Resistance	Patients with isolates resistant to both INH and RIF.¹⁶
Resistance to INH	Growth of MTB was >1% with 0.1 μg/mL (low) and 0.4 μg/mL (high).^17,18

TB: tuberculosis, INH: isoniazid, RIF: Rifampicin, MTB: Mycobacterium tuberculosis complex

Table 2

- Demographic and clinical characteristics of subjects (N=105).

Characteristics	n (%)
Age
1-20	9 (8.6)
21-40	47 (44.8)
41-60	25 (23.8)
61-90	24 (22.9)
Mean	42.93
Median x-bar	38.00
Standard deviation	21.329
Gender
Male	68 (64.8)
Female	37 (35.2)
Nationality
Saudi	85 (81.0)
Non-Saudi	19 (18.1)
Not mentioned	1 (0.9)
Comorbidities
Diabetes mellitus	28 (26.7)
Hypertension	22 (21.0)
Ischemic heart disease	8 (7.6)
Human immunodeficiency virus	1 (0.95)
Malignancy	7 (6.7)
Immunosuppression	5 (4.8)
Other comorbidities	30 (28.6)
No comorbidities	50 (47.6)
Previous treatment for tuberculosis
Yes	6 (5.7)
No	99 (94.3)
Site of infection
Unknown	6 (5.7)
Pulmonary	39 (37.1)
Extrapulmonary	34 (32.4)
Disseminated^*	26 (24.8)

Values are presented as numbers and percentages (%).
↵* Disseminated infection involves both the pulmonary and extrapulmonary systems. HIV: Human immunodeficiency virus

Table 4

- Frequency and distribution of isoniazid resistance (N=9).

Table 5

- Outcomes between patients with isoniazid-monoresistant and those with non-isoniazid resistance (n=105).

Outcome	(n=9)	(n=96)	P-value
Duration of treatment (months)	Resistant	Nonresistant
1-6	0	15 (16.3)	0.581
7-9	3 (3.3)	32 (34.7)
10-12	2 (22.2)	9 (9.2)
>12	1 (11.1)	7 (6.1)
Loss to follow-up	3 (33.3)	33 (33.3)
Mean x-bar (excluding loss to follow-up)	12.00	9.46
Standard deviation	6.033	3.711
Side effects	Resistant	Nonresistant	0.079
Drug-induced hepatitis	1 (11.1)	12 (12.2)
Blurry vision	1 (11.1)	1 (1.02)
Peripheral neuropathy	1 (11.1)	1 (1.02)
Joint pain	0	4 (4.1)
No side effects	6 (66.67)	71 (72.5)
Other side effects	0	9 (9.2)
Clinical outcome	Resistant	Nonresistant
Successful treatment	5 (55.56)	51 (53.13)	0.988
Unsuccessful treatment	1 (11.11)	12 (12.5)
→ Relapse	0	4
→ Death	1	8
Loss to follow-up	3 (33.33)	33 (34.38)
Length of hospitalization (days)	Resistant	Nonresistant
1-25	1	43	0.130
26-50	2	20
>50	1	11
Unavailability	5	22
Mean x-bar (excluding loss to follow-up)	38.00	36.96
Standard deviation	20.314	53.475