Of all the patients, three patients in group A and one patient in group B were excluded from the study; as a result, the remaining 96 patients were randomly assigned to the two groups receiving sequential therapy regimen with levofloxacin (49 patients) and triple therapy regimen (47 patients). The mean age of the patients in the sequential therapy group and triple therapy group was 33.29 ± 1.54 years and 45.53 ± 2.17 years, respectively. There was a significant difference between the two treatment groups in terms of the mean age (p = 0.00). However, there was no significant difference between the two treatment groups in terms of patients’ sex distribution (p = 0.57). Moreover, there was also a significant difference between the two treatment groups in terms of the distribution of patients in different education groups (p = 0.00). Table 1 presents the data on patients’ age, sex, and education level.

Of the patients in the two groups, 67.3% of the patients in the sequential therapy group and 66% of the patients in the triple therapy group had negative HpSA (H. pylori Stool Antigen); there was no significant difference between the two treatment groups in terms of the eradication of H. pylori (p = 0.99) (Table 2). In addition, concerning the side effects of the medications, one person (2%) in the sequential therapy group (because of the nausea caused by amoxicillin) and one person (2.1%) in the triple therapy group (because of the cramps caused by clarithromycin) were unable to tolerate the drug. However, the rest of the participants in this study did not report any treatment-specific complaints.

The results of stool antigen test were used to assess the effects of patients’ age on the efficacy of sequential therapy and triple therapy for the eradication of H. pylori. The results showed that when comparing the patients aged 40 years and younger between the two treatment groups, there was no significant difference between them in terms of the treatment outcome (p = 0.32); however, when comparing patients aged over 40 years, there was a significant difference between the two treatment groups in terms of response to treatment. Accordingly, the response to treatment was better in the triple therapy group (p = 0.045) (Table 3).

The effects of education levels on eradication of H. pylori were assessed; according to the results, the responses to the treatment in sequential therapy group were significantly different between different education groups (p = 0.01), but in the triple therapy group there was no significant difference between different education groups in terms of the response to treatment (p = 0.46) (Table 4). There was a significant difference between the two groups of patients with education levels lower than high-school diploma and academic education in terms of response to treatment (p = 0.048). There was also a slightly significant difference between the two groups of patients with high-school diploma and academic education in terms of response to treatment (p = 0.063). However, there was no significant difference between the two groups of patients with an education level lower than high school diploma and with high school diploma in terms of response to treatment (p = 0.89).

The effect of sex on eradication of H. pylori was also assessed. In the triple therapy group, there was no significant difference between females and males in terms of response to treatment (p = 0.64); however, in the sequential therapy group, a significant difference was observed between females and males in terms of response to treatment (p = 0.009). Accordingly, the response to treatment was better in males than females in the sequential therapy group (Table 5).

Click here for Table 1: Demographic data of patients in the two treatment groups receiving triple therapy regimen and sequential therapy regimen to eradicate H. pylori

Table 2: Comparison of the results of stool antigen test between the two treatment groups receiving triple therapy regimen and sequential therapy regimen to eradicate H. pylori

* p < 0.05 is considered as significant

Table 3: Comparison of the effects of patients’ age on the efficacy of treatment (based on the results of stool antigen test) between the two groups receiving triple therapy regimen and sequential therapy regimen to eradicate H. pylori

* p < 0.05 is considered as significant

Table 4: Comparison of the effects of patients’ education on the efficacy of treatment (based on the results of stool antigen test) between the two groups receiving triple therapy regimen and sequential therapy regimen to eradicate H. pylori
* p < 0.05 is considered as significant

Table 5: Comparison of the effects of patients’ sex on the efficacy of treatment (based on the results of stool antigen test) between the two groups receiving triple therapy regimen and sequential therapy regimen to eradicate H. pylori

DISCUSSION

This study was conducted to compare standard triple therapy regimen with sequential therapy regimen containing levofloxacin used for the eradication of H. pylori in patients with gastrointestinal infection caused by H. pylori. H. pylori eradication rate was 67.3% in the sequential therapy regimen and 66% in standard triple therapy regimen. As the main goal of treatment is to eradicate the infection in 85-95% of the patients; however, because of the lower treatment success rates observed in this research, hence, these two regimens in this study is not recommended.
Several studies have been conducted on standard triple therapy in Iran. In a study by Aminian and colleagues, the regimen consisted of omeprazole 20 mg twice a day, amoxicillin 1 g twice a day, and clarithromycin 500 mg twice a day which had been administered for 10 days with the eradication rate of 90.7% [30]. Moreover, Keshavarz and colleagues used the above-mentioned treatment regimen for seven days and reported an eradication rate of about 87.5% [31].

Furthermore, one of the most common causes of treatment failures could be the emergence of new antibiotic-resistant bacterial strains [32]. In this study, the emergence of H. pylori strains resistant to the antibiotics might have been a cause of treatment failure. In a similar study conducted by Polat and colleagues, of a total of 72 patients receiving

sequential regimen containing levofloxacin, 65 patients were affected by gram-negative bacteria, while of a total of 67 patients receiving standard triple therapy regimen, only 34 patients were affected by gram-negative bacteria [29], which may refer to the fact that in different geographic areas, bacterial resistance to antibiotics might be different.

Because of the common complication of furazolidone and high cost of clarithromycin, many Iranian physicians routinely prefer to use metronidazole, amoxicillin, bismuth, and omeprazole for H. pylori eradication [4]. In this study, the patients in triple therapy for ten days received omeprazole 20 mg twice a day, amoxicillin 1 g twice a day, and clarithromycin 500 mg twice a day; however, the patients in the sequential therapy group for five days received omeprazole 20 mg twice a day and amoxicillin 1 g twice a day; in the next five days, they received levofloxacin 250 mg twice a day, omeprazole 20 mg twice a day, and tinidazole 500 mg twice a day. In fact, H. pylori resistance to these antibiotics might have been a reason for reduced efficacy of the regimens in eradication of the bacterial infection in this research. Long-term clarithromycin monotherapy for the treatment of respiratory tract diseases could indeed lead to the increased resistance to this antibiotic. H. pylori resistance to clarithromycin might also be the most important factor explaining the failure of treatment regimens, particularly triple therapy, used for the eradication of infection [33-36]. Moreover, it is reported that the optimal efficacy of metronidazole-based triple and quadruple drug regimens in western countries is about 80-95% [5, 15]. However, due to the high rates of resistance to metronidazole in Iran [37,38], the eradication rate is usually not optimal [4, 39]. In this study, the use of the mentioned treatment regimens may have resulted in low rates of H. pylori eradication which is consistent with the findings of Zhou and colleagues’ study (in 2014) who reported the H. pylori resistance to sequential and triple therapy regimens [40].

Studies which have compared sequential and triple therapy regimens have reported different results, as some of them reported the superiority of sequential treatment regimen while other others have reported the superiority of triple therapy regimen [32, 41-44]. In a study conducted by Khaleghi and colleagues, the patients with chronic dyspepsia were classified into two groups each consisting of 80 people [45]. One of the groups received omeprazole and amoxicillin for the first five days and then omeprazole, furazolidone, and clarithromycin for the next nine days; the other group received quadruple regimen for 14 days consisting of omeprazole, amoxicillin, clarithromycin, and bismuth. Of all, 50.9% of the patients in the sequential therapy group and 49.1% of the patients in the second group were cured, and the difference was not statistically significant [45]. In another study, Kaboli and colleagues investigated 140 patients with dyspepsia and classified them into two groups; the first group received omeprazole, amoxicillin, and clarithromycin for 14 days and the second group (sequential group) first received omeprazole and amoxicillin for five days, and then omeprazole, clarithromycin, Tinidazole for the next five days; there was no significant difference between the two groups in terms of H. Pylori eradication [46]. Zullo and colleagues studied 36 patients who received rabeprazole 20 mg twice a day, levofloxacin 250 mg twice a day, and amoxicillin 1 g twice a day. According to the results, H. pylori was successfully treated in 30 patients [47]. In fact, comparing with the sequential regimen used in this study and the obtained results, it can be concluded that the H. pylori strains resistant to levofloxacin might have been caused by the indiscriminate use of antibiotics in this region.

In the present study, considering people in the age group over 40 years, the eradication rate in the triple therapy group (69%) was higher than the eradication rate in the sequential therapy group (33.3%) (p = 0.045). To justify these results, it can be concluded that the use of sequential therapy regime, especially for older people, is more difficult than that of triple therapy regimen. The more complex schedule for taking sequential therapy regimen, especially in people over 40 years of age, may increase the risk of treatment failure in this study. Nevertheless, Hashemi and colleagues (in 2007) reported that patients’ age had no significant relationship with the eradication of H. pylori [4].
Higher education level is reported as a factor influencing the eradication of H. pylori infection. In this study, the highest level of eradication was observed in people with an academic degree. These findings are in line with other studies in this field that have proven H. pylori infection is lower among people with higher education levels [48-50]. People with lower education level are indeed at a higher risk of infection than those with higher education levels; such a negative relationship is also observed between parents’ education and infection [51,52].

The results of this study showed that men had a better response to treatments than women. It is inconsistent with the results of studies by Misattari and Hashemi which reported no statistically significant difference between men and women in terms of the response to treatments; however, in this study in patients in the triple therapy group, there was no significant difference between the two sexes in terms of response to treatments [4, 32, 53].

Given the low rate of H. Pylori eradication by the sequential and triple therapy regimens observed in this study, further research must be conducted to study the resistance of the bacteria to the studied treatment lines and antibiotics in Iran. Considering the results of this study, it is also recommended to utilize other treatment regimens to achieve higher rates of eradication. It is also suggested to use more effective and simple treatment regimens for older people and those with lower education levels.

CONCLUSION

The use of sequential therapy regimen containing levofloxacin for the eradication of H. pylori results in outcomes which are less than the optimal levels. However, further studies in this field are needed to be carried out with larger sample size in different places.

Acknowledgments
This study was extracted from M.D thesis of Kian Kaveh-Zadeh (Thesis #1214).

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