Results
The Study Population
A total of 98 patients were screened for the study. More than half of them, 58 patients, were excluded as they did not meet the inclusion criteria (n = 35), refused to participate (n = 16), or had kidney stones (n = 2), depression (n = 2), dental problems (n = 1), malignancy (n = 1) or hyperparathyreosis (n = 1). All 40 enrolled, eligible patients completed the one-year follow-up (Figure 1).
Figure 1.
Study flowchart.
The clinical characteristics of study participants at baseline are displayed in Table 1. The mean LBP duration was 293 days, initial LBP intensity on VAS 6.7, leg pain on VAS 2.9 and the ODI score was 32%. Altogether 19 patients in the ZA group and 18 in the placebo group had a mixed-type M1/2 lesion. MC were most commonly (70%) situated at L4/5 or L5/S1. The ZA and placebo groups were similar as regards the demographic and background characteristics of all patients at baseline, although there were numerically more men (15 vs. 11) in the ZA group than in the placebo group (Table 1).
Treatment Differences
The mean difference (MD) between the treatment groups in the primary outcome, intensity of LBP, significantly favoured ZA at one month (MD 1.4; 95% CI 0.01 to 2.9) while at one year no significant difference was observed (MD 0.7; 95% CI −1.0 to 2.4; Table 2). The proportion of patients with at least 20% improvement in intensity of LBP and PASS both favoured the ZA treatment at one month: ZA 55% vs. placebo 25% (p = 0.105) and ZA 50% vs. placebo 20% (p = 0.096), respectively.
Of the secondary outcomes, the improvement in ODI, favored non-significantly ZA at 1 month, the adjusted between-group difference being 6.0% (95% CI −0.6 to 13), but not at one year (Table 2). Similarly, side bending (to right and left) non-significantly favoured the ZA treatment at one month but not at one year (Table 2). We observed no differences between the treatment groups at any time point in leg pain intensity (Table 2), total RAND-36, or in the physical and mental components of RAND-36 (Table 3).
At baseline, there were no differences in self-reported use of non-steroidal anti-inflammatory drugs (NSAIDs) between the treatment groups, whereas at one year, only 20% of patients in the ZA group used NSAIDs versus 60% in the placebo group (P = 0.022). No significant differences were observed in patient-reported days of sick leave (data not shown).
Safety Parameters
Reported adverse events (AE) were common and occurred more frequently in the ZA group, especially immediately after the infusion. AEs were mostly mild in nature (Table 4). Despite prophylaxis, acute post-infusion phase reactions (fever, headache, myalgia, arthralgia, pain, nausea and flu-like symptoms) were observed in 19/20 patients in the ZA vs. 7/20 patients in the placebo group. As expected, the majority of the acute phase reactions were of mild to moderate severity as rated by the investigator and typically resolved within three days of onset. One event met the criteria for serious adverse effect (SAE) in the ZA group; a male patient had sinusitis requiring temporary hospitalization after the infusion.
BMC Musculoskelet Disord. 2014;15(64) © 2014 BioMed Central, Ltd.
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