TABLE 6.
Linear mixed model, generalized estimating equation, and generalized linear mixed model analyses examining the change in clinicopathological variables over time in the per‐protocol cats (n = 44) during the study period.
| Variables | Group | Time | Group × Time |
|---|---|---|---|
| BCS a (“1‐3”, “4‐9”) | .75 | .08 | .66 |
| MCS a (“0”, “1”, “2”, “3”) | .51 | .17 | .87 |
| Body weight a (kg) | .6 | .002 | .62 |
| Albumin (g/dL) | .71 | .74 | .77 |
| ALP (U/L) | .68 | .51 | .29 |
| ALT a (U/L) | .57 | .623 | .4 |
| Chloride (mEq/L) | .64 | .1 | .65 |
| Creatinine (mg/dL) | .6 | .73 | .68 |
| Ln[FGF23] (pg/mL) | .84 | .02 | .25 |
| Glucose (mg/dL) | .99 | .19 | .28 |
| Venous HCO3 − (mEq/L) | .76 | .01 | .05 |
| Ionized calcium (mg/dL) | .21 | .91 | .01 |
| PCV (%) | .3 | .21 | .73 |
| Venous pH a | .57 | .47 | .31 |
| Phosphate (mg/dL) | .37 | .26 | .55 |
| Potassium (mEq/L) | .56 | .64 | .71 |
| Ln[PTH] (pg/mL) | .14 | .93 | .49 |
| SBP (mmHg) | .64 | .83 | .91 |
| SDMA (μg/dL) | .61 | .39 | .78 |
| Sodium a (mEq/L) | .32 | .98 | .16 |
| Total calcium (mg/dL) | .21 | .91 | .01 |
| Total magnesium (mg/dL) | .88 | .01 | .02 |
| Total protein (g/dL) | .81 | .75 | .96 |
| Urea (mg/dL) | .18 | .71 | .44 |
Note: Summary of P‐values for all variables included in the model. Group represents cats in “control phosphate‐restricted diet (PRD)” or “magnesium‐enriched PRD” group based on the allocated trial diet according to the randomization list. Outcome variables showing significant change over time and between groups (P ≤ .05) are highlighted in bold. The unit used for time was month (30.4 days). A significant effect in the group column indicates a significant difference between the 2 groups at baseline for a given parameter (the start of the regression line at time 0). A significant effect of Group × Time interaction indicates that the rate of change of the outcome variable differs significantly between groups (“control PRD” vs “magnesium‐enriched PRD”) over time. If Group × Time was not significant, and the effect of Time was significant, this indicates no difference in the rate of change of the outcome variable between groups; however, the overall gradient of the outcome variable plotted against time (with the data from all groups combined) differs significantly from zero.
Abbreviations: ALP, alkaline phosphatase; ALT, alanine aminotransferase; BCS, body condition score; HCO3 −, bicarbonate; ln[FGF23], log‐transformed fibroblast growth factor‐23; ln[PTH], log‐transformed parathyroid hormone; MCS, muscle condition score; SBP, systolic blood pressure; SDMA, symmetric dimethylarginine.
Only the case number of each individual cat was included as random effect in the model.