Effect of Parathyroid

Hormone (1-34) on Fractures and Bone Mineral Density in Postmenopausal

Women with Osteoporosis

Elise Miller

Variables of Interest

Since we are dealing with Chi-Since we are dealing with Chi-square, there are 2 categorical square, there are 2 categorical variables.variables.

Women were placed into 3 groups:Women were placed into 3 groups: 1.)Placebo1.)Placebo

N=544N=544 2.)PTH 20-2.)PTH 20-µg µg

N=541N=541 3.)PTH 40-3.)PTH 40-µgµg

N=552N=552

Variables of Interest cont.

The second variable was whether The second variable was whether or not new nonvertebral fractures or not new nonvertebral fractures had developed since the baseline had developed since the baseline examinations. examinations.

Or whether or not new fragility Or whether or not new fragility fractures developed.fractures developed.

From Table 3

To Compare the P-Values…

Placebo and Treatment were taken Placebo and Treatment were taken as the explanatory variables.as the explanatory variables.

Whether there were new fractures Whether there were new fractures was used as the response was used as the response variable.variable.

Minitab Procedure

For example: For example: Placebo: N=544Placebo: N=544

Fracture= 53Fracture= 53 No Fracture= 491No Fracture= 491

PTH 20: N=541PTH 20: N=541 Fracture=34Fracture=34 No Fracture= 507No Fracture= 507

These numbers get inputted into MiniTab to find the P-value.

MiniTab Output

C1 C2 TotalC1 C2 Total 1 53 491 5441 53 491 544 43.62 500.3843.62 500.38 2.017 0.1762.017 0.176

2 34 507 5412 34 507 541 43.38 497.6243.38 497.62 2.028 0.1772.028 0.177

Total 87 998 1085Total 87 998 1085

Chi-Sq = 4.398, DF = 1, Chi-Sq = 4.398, DF = 1, P-Value = 0.036P-Value = 0.036

Procedure cont.

The same procedure was done The same procedure was done comparing each dose for total comparing each dose for total fracture and fragility fracture.fracture and fragility fracture.

P-Values

Placebo vs. 20Placebo vs. 20µg (Fracture)µg (Fracture) By hand: p=.036By hand: p=.036 Given: p=.04Given: p=.04

Placebo vs. 40µg (Fracture)Placebo vs. 40µg (Fracture) By hand: p=.015By hand: p=.015 Given: p=.02Given: p=.02

Placebo vs. 20µg (Fragility) Placebo vs. 20µg (Fragility) By hand: p=.015By hand: p=.015 Given: p=.02Given: p=.02

Placebo vs. 40µg (Fragility)Placebo vs. 40µg (Fragility) By hand: p=.012By hand: p=.012 Given: p=.01Given: p=.01

Consequences of Error

Type 1:Type 1: Researchers would give out a drug Researchers would give out a drug

that doesn’t have any benefit to that doesn’t have any benefit to eliminating fracture.eliminating fracture.

Type 2:Type 2: The PTH would be considered The PTH would be considered

ineffective and would not make it to ineffective and would not make it to the market.the market.

Adverse Effects

No significant differences among No significant differences among the three groups regarding death.the three groups regarding death.

Because the null states that both Because the null states that both treatment and placebo have the treatment and placebo have the same risk factors….. Would the same risk factors….. Would the null be accepted or rejected?null be accepted or rejected?

Regarding death, the null would be Regarding death, the null would be accepted because there was not accepted because there was not significant difference between significant difference between treatment and placebo.treatment and placebo.

What if researchers were wrong?

What type of error would be What type of error would be committed?committed?

Type I: Type I: This error would mean that treatment This error would mean that treatment

actually has risk of death.actually has risk of death.

Potential Bias

Like most medical research, bias is Like most medical research, bias is considered and ultimately considered and ultimately eliminated.eliminated.

People had to meet certain criteria People had to meet certain criteria in order to participate.in order to participate.

Research Conclusions

Treatment of postmenopausal Treatment of postmenopausal osteoporosis with parathyroid osteoporosis with parathyroid hormone (1-34) decreases the risk of hormone (1-34) decreases the risk of fracture.fracture.

Increases total-body bone mineral Increases total-body bone mineral density.density.

In order to have minimal side effects, In order to have minimal side effects, with higher bone density results and with higher bone density results and minimal fracture, the 20minimal fracture, the 20µg dose is µg dose is the most beneficial.the most beneficial.