Patient characteristics
Table 1 illustrates and compares the characteristics of the patients in MSMP and MRMP groups. The patient demographics were comparable in both groups, the male to female ratio was 1:1.5, the mean age in both groups were 8 years old (s.d±4years in MSMP and s.d±3years in MRMP). None of the children had chronic respiratory conditions defined as conditions requiring long-term treatment for respiratory disease. Clinical features on presentation such as fever duration prior to admission, presenting symptoms of fever, cough, rash and tachypnoea (according to age adjusted ranges) were comparable and no significant differences between the two groups were observed. The average duration of achieving normal respiratory rate with treatment were slightly longer in the MRMP group (52hours) compared to the MSMP group (41hours), but they were not statistically significant (P=0.648).
Laboratory and clinical features
Laboratory findings (previously mentioned including WCC, CRP, ESP, ALT, CA) were compared. Both groups did not show a significant difference in raised or lowered WCC, CRP levels were elevated in both groups (90% in MSMP and 94% in MRMP). There were an equal number of patients with raised ALT in both groups. CA was not routinely taken in this group of patients. Only 1 patient with MSMP had a raised CA titre (≥64) and 3 out of 6 patients with MRMP had a raised titre.
Overall there were no significant laboratory differences between patients with MSMP and MRMP.
Given the large variation of resistance in different parts of the world, other characteristics such as travel history within the last two weeks particularly to China were studied in the two groups. Twenty four percent of all patients with Mycoplasma associated pneumonia had a history of travel two weeks prior to admission and the majority visited China. In the MSMP group, 10 patients out of 12 with travel history (83%) had travelled to China and comparatively, 10 out of 14 patients (71%) in the MRMP group with travel history had travelled to China. But these results were statistically insignificant.
The presenting clinical condition and complications were compared. All patients presented with chest radiograph with changes compatible with pneumonia, none had lobar collapse and 5% of all patients (n=5) diagnosed with Mycoplasma associated pneumonia had evidence of pleural effusion. There was higher incidence of developing this complication in patients with MRMP although not statistically significant. One patient in MSMP group had pleural effusion (20%) and the remaining 4 patients with effusion had MRMP (80%).
Both MSMP and MRMP had similar percentage of patients requiring oxygen within hospitalization. The overall duration of oxygen use was shown to be greater in the MRMP group than in the MSMP group. The mean duration of oxygen use in MSMP was shorter at 60 hours (s.d±39 hours), compared to the mean duration of 102 hours (± of 76 hours) in MRMP, but not statistically significant.
Information on the outcome such as the total duration of fever, prior to admission, time of defervescence (TTD), length of stay and comparing outcomes with the use of doxycycline were analyzed.
Co-infection was detected in 8 patients and the associated pathogens include Influenza A, Parainfluenza, Streptococcus pneumoniae andHaemophilus influenzae . They were excluded from the subgroup analysis for TTD. Another 2 patients were admitted for concomitant conditions contributing to the febrile episode, which was acute lymphoblastic leukaemia and hemorrhagic bullous myringitis and were excluded. One patient was excluded due to early self-discharge hence insufficient data for analysis.
Other patients excluded from the subgroup analysis were those with prior use of macrolide before admission and those never used macrolide or switched from macrolide to doxycycline within the course of admission were excluded from the TTD analysis. After exclusion, a total of 74 patients were eligible for this sub-group analysis. Comparing patients with MSMP and MRMP, there was a statistical significance in mean total duration of fever after admission, which were 1.6 days (±1 day) and 2.8days (±2.3 days) respectively. TTD between patients with MSMP and MRMP at different cut offs were compared. In the MSMP group, 40% of the patients achieved defervescence within 24hours and 83% within 48 hours (both not statistically significant). The results show a statistically significant 96% of the MSMP patients had achieved defervescence by 72 hours and by comparison, only 71% of the patients with MRMP had achieved defervescence at this cut off point. (P=0.005).