Transcript Effect of Parathyroid Hormone (1-34) on Fractures and Bone Mineral

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-square,
there are 2 categorical variables.
 Women were placed into 3 groups:


1.)Placebo
 N=544

2.)PTH 20-µg
 N=541

3.)PTH 40-µg
 N=552
Variables of Interest cont.
The second variable was whether or
not new nonvertebral fractures had
developed since the baseline
examinations.
 Or whether or not new fragility
fractures developed.

From Table 3
To Compare the P-Values…
Placebo and Treatment were taken as
the explanatory variables.
 Whether there were new fractures was
used as the response variable.

Minitab Procedure

For example:
 Placebo:


Fracture= 53
No Fracture= 491
 PTH


N=544
20: N=541
Fracture=34
No Fracture= 507
These numbers get inputted into MiniTab to find the P-value.
MiniTab Output
C1
C2 Total
1
53
491 544
43.62 500.38
2.017 0.176
2
Total
34
507 541
43.38 497.62
2.028 0.177
87
998 1085
Chi-Sq = 4.398, DF = 1, P-Value = 0.036
Procedure cont.

The same procedure was done
comparing each dose for total fracture
and fragility fracture.
P-Values

Placebo vs. 20µg (Fracture)



Placebo vs. 40µg (Fracture)



By hand: p=.015
Given: p=.02
Placebo vs. 20µg (Fragility)



By hand: p=.036
Given: p=.04
By hand: p=.015
Given: p=.02
Placebo vs. 40µg (Fragility)


By hand: p=.012
Given: p=.01
Consequences of Error

Type 1:


Researchers would give out a drug that
doesn’t have any benefit to eliminating
fracture.
Type 2:

The PTH would be considered ineffective
and would not make it to the market.
Adverse Effects
No significant differences among the
three groups regarding death.
 Because the null states that both
treatment and placebo have the same
risk factors….. Would the null be
accepted or rejected?
 Regarding death, the null would be
accepted because there was not
significant difference between
treatment and placebo.

What if researchers were wrong?
What type of error would be
committed?
 Type I:


This error would mean that treatment
actually has risk of death.
Potential Bias
Like most medical research, bias is
considered and ultimately eliminated.
 People had to meet certain criteria in
order to participate.

Research Conclusions
Treatment of postmenopausal
osteoporosis with parathyroid hormone
(1-34) decreases the risk of fracture.
 Increases total-body bone mineral
density.
 In order to have minimal side effects,
with higher bone density results and
minimal fracture, the 20µg dose is the
most beneficial.
