Table 2.
Between-Treatment Comparison in Percentage Change in Bone Density and PINP at Year 4.5 and Year 6 Relative to Year 3a
| Location | Visit | Treatment | n | Mean change (%) | Mean % difference (95% CI) | p Value |
|---|---|---|---|---|---|---|
| Femoral neck | Year 4.5 | Z6 | 525 | 0.59 | 0.53 (−0.02, 1.08) | 0.06 |
| Z3P3 | 544 | 0.06 | — | — | ||
| Year 6b | Z6 | 451 | 0.24 | 1.04 (0.43, 1.65) | <0.001 | |
| Z3P3 | 470 | −0.80 | — | — | ||
| Total hip | Year 4.5 | Z6 | 525 | 0.37 | 0.55 (0.18, 0.92) | 0.004 |
| Z3P3 | 544 | −0.18 | — | — | ||
| Year 6 | Z6 | 451 | −0.36 | 1.22 (0.75, 1.70) | <0.0001 | |
| Z3P3 | 470 | −1.58 | — | — | ||
| Lumbar spine | Year 4.5 | Z6 | 101 | 2.41 | 1.40 (0.38, 2.42) | 0.01 |
| Z3P3 | 102 | 1.01 | — | — | ||
| Year 6 | Z6 | 100 | 3.20 | 2.03 (0.76, 3.29) | 0.002 | |
| Z3P3 | 84 | 1.18 | — | — | ||
| Distal radius | Year 4.5 | Z6 | 100 | 0.45 | 1.32 (0.40, 2.24) | 0.01 |
| Z3P3 | 99 | −0.86 | — | — | ||
| Year 6 | Z6 | 96 | −0.12 | 0.37 (−0.71, 1.45) | 0.50 | |
| Z3P3 | 82 | −0.49 | — | — | ||
| PINP | Year 4.5 | Z6 | 402 | −23% | 47% | <0.001 |
| Z3P3 | 431 | +24% | ||||
| Year 6 | Z6 | 370 | +19% | 14% | 0.0001 | |
| Z3P3 | 395 | +33% |
CI = confidence interval; PINP = serum procollagen type I N-terminal propeptide.
n is the number of patients with values at year 3 and the follow-up visit. 95% CI is calculated based on a t-distribution for BMD. The p value is obtained from ANOVA with treatment and region as explanatory variables.
The 4.5-year point is 6 months after year 4 infusion: 6-year point is 12 months after year 5 infusion.
Using the last postrandomization observation carried forward to impute missing data, the difference in femoral neck BMD change between treatment groups was 0.71% (95% CI 0.14%, 1.28%; p = 0.015). Using multiple imputation, the difference was 0.88% (95% CI 0.28%, 1.49%; p = 0.004).