How was this calculation made?

We set out to provide a general estimate of the time required for two different fragility fracture prevention strategies

1. BMD-first strategy: Estimates of BMD frequency were based on the 2010 guidelines from Osteoporosis Canada.
2. Risk assessment-first strategy: Estimates were based on the recommendations of the Canadian Task Force on Preventive Health Care (hereafter the Task Force).

Primary care clinician’s practice

1200 adult patients years of age (up to 84 years old at the start)

• 600 patients are 0-49 years of age
• 300 patients are 50-64 years of age
• 300 patients are 65-84 years of age.

Half of the patients are women and half are men (see Appendix 1)

We considered screening happened until 84 years of age.

Follow-up of the cohort of patients for 25 years

25 years of follow-up was chosen to represent a family physician’s years of practice once stabilized, recognizing that many family physicians continue to practice for more than 25 years.

Time needed for screening

These times were estimated based on a convenience survey distributed in April 2023 by email and social media (see Appendix 2 for details)

BMD -first strategy (not recommended by the Task Force)

Ordering a BMD without risk calculation: 2.2 minutes

Dealing with a BMD result (low-to-moderate risk or a high-risk in an individual already treated): 2.2 minutes (certain high-risk results might take longer but we left this duration to be conservative in our estimates – this probably underestimates the time needed for this strategy)

Discuss +/- prescribe preventive medication (first high risk BMD): 8.2 minutes

Risk assessment -first strategy (recommended by the Task Force)

Calculate FRAX, inform the patient of her risk, engage in shared decision-making (SDM) to inform if she would consider preventive medication and wants a BMD to help her decide: 6.9 minutes

Ordering a BMD after risk calculation with FRAX: 2.2 minutes

Discussion post-BMD +/- prescribe preventive medication: 8.2 minutes (this discussion is probably shorter as SDM was done before the BMD, but we left this duration to be conservative in our estimates – This probably overestimates the time needed for this strategy)

Number of individuals screened for every 5-year period (over 25 years)

Since we are following patients for 25 years, only patients aged 30 years and older at the beginning of the screening period would be eligible for inclusion during the last 5 years of the 25-year follow-up period (i.e., they would be between 50 to 54 during the last 5 year of the 25 years of follow-up). We used Canadian statistics to calculate the proportion of women and men in our sample patient population to generate the number of patients by 5-year age groups and sex (for those 65 to 84 years old). (See Appendix 3 for details).

Osteoporosis Canada also recommended screening women and men 50-64 years if they had risk factors. Risk factors identified in the Osteoporosis Canada 2010 recommendations included:

• Fragility fracture
• Prolonged use of glucocorticoids or other high-risk medication
• Parental hip fracture
• Vertebral fracture or osteopenia identified on radiography
• Excessive alcohol intake
• Smoking
• Low body weight (< 60 kg) or major weight loss (> 10% of body weight at age 25)
• Rheumatoid arthritis
• Other disorders strongly associated with osteoporosis

Of these, the only risk factor that can be easily estimated is the smoking rate. Estimating how many individuals within a practice would have at least one of the other above-listed risk factors (except for smoking) was not feasible. Hence, we could not estimate the patient population eligible, the number of BMD screens, nor the time needed for the BMD-first strategy for patients with risk factors 50-64 years of age (see Appendix 4).

Repetition of screening (i.e., Number of Screens Per Person over 25 years)

BMD -first strategy (not recommended by the Task Force)

Using the 2010 Osteoporosis Canada recommendations, we applied estimates for rescreening patients from 65-84 years of age over 25 years and assumed that all patients rescreened remained in the same risk category (low to moderate or high risk). Although the re-screening frequencies for moderate risk are more similar to high risk, we conservatively grouped low and moderate-risk strategies. The calculation and additional assumptions are shown in Appendix 4. 

Risk assessment -first strategy (recommended by the Task Force)

Screening with risk assessment was calculated with a total of 2 screenings as no evidence supports the benefit to rescreen before 8 years (see Appendix 5 for details)

Percentage of women that will consider having a BMD in the risk-assessment first strategy

A study by Montori et al. (2011) shows that less than half of the women (44%) would choose medication when informed of their risk with a decision aid. As the number of women who would choose a BMD is unknown, we used this same proportion as our estimate of how many women would agree to a BMD after shared decision-making (SDM).

Estimated number of hours for varied screening options

The following options estimate the number of hours of clinician time over different screening strategies, over 25 years of follow-up.

Option 1: Risk assessment-first for women starting at 65 years

300 (150 X 2): 300 X 6.9 minutes =  35 hours

132 order BMD (44%) X 2.2  minutes =   5 hours

132 discussions after BMD X 8.2 minutes =  18 hours see note 1

Total: 58 hours  

Option 2: BMD-first strategy for women starting at 65 years.

1452 BMD ordered X 2.2 minutes =  53 hours

(850 + (602-56)) results with no medication discussions X 2.2 minutes = 51 hours see note 2

56 prescriptions of medication discussion X 8.2 minutes = 8 hours

Total:  112 hours  

Option 3: BMD-first strategy for women and men starting at 65 years.

2822 BMD ordered X  2.2 minutes  = 103 hours

(2102+(720-67)) results with no medication discussions X 2.2 minutes =101 hours see note 2

67 prescriptions of medication discussion X 8.2 minutes=  9 hours

Total:  213 hours

Option 4: BMD-first strategy for women and men with risk factors starting at 50 years

Unable to calculate owing to lack of estimates on population with risk factors (other than smoking). Note, this would include low, moderate and high-risk BMDs done for patients with both risk factors between 50-64 years and who would then continue to be screened at age 65+ years.

See Appendix 3 for details on the calculation and additional assumptions

Total BMD for women: (602 (HR) + 850(LR)) (65-84 years) = 1452

Total BMD for men: (118 (HR)+ 1252 (LR)) (65-85 years) = 1370

TOTAL BMD: 2822

Note 1: The second discussion in the risk-assessment first strategy is probably shorter as SDM was done before the BMD, but we left this duration to be conservative in our estimates – This probably overestimates the time needed for this strategy

Note 2: Certain abnormal results might take longer to handle but we use this duration for all the results to be conservative in our estimates – This probably underestimates the time needed for this strategy

For the number of screening repetitions for the risk assessment first, see the assumptions and calculations in Appendix 5

APPENDIX 1

Our assumptions say that half of the patients above 50 are women and half are men

Source: According to statistics from 2022, there were 14,487,356 individuals 50-85 years of age, out of which 6,864,910 were men (48.5%) and 7,282,446 women (51.5%)

APPENDIX 2

The time needed for each step in the screening

These times were approximated based on data from a survey distributed in April 2023 by email and social media.

90 family physicians answered the questions (see the survey questions below)

The times below are a weighted mean of the answers from the survey

• we used the upper limit of the provided times to make the calculations (ex: if the answer was 3-4 minutes we calculated with 4 minutes)
• for the answer “more than 15 minutes” we used 18 minutes
• for the last question, 11 individuals who answered that they have never used a decision aid were removed from the denominator. As such, the denominator was 79.

Q1 : Combien de temps cela vous prend-il pour demander une ostéodensitométrie pour un(e) patient(e) (explication du test au patient, remplir le formulaire, le donner ou le transmettre au patient)      

Order a BMD:

3.3%-30sec: 1                                    

8,9%-60 sec: 5.5

31.1%-90sec: 28                                            

12.2%-120sec: 14.6

21.1%-180sec: 38.4

11.1%-240sec: 26.6

12.2%-300sec: 36.6

Weighted mean: 2.2 minutes

Q2 : Combien de temps cela vous prend-il pour gérer un résultat normal d’ostéodensitométrie (lecture du résultat, consultation du dossier au besoin, classer le test)

Normal result:

11.1%-30sec : 3.3

26.7%-60sec : 16

17.8%-90sec : 16                                         

6.7%-120sec : 8

16.7%-180sec : 30

8.9%-240sec : 21.3

12.2%-300sec : 36.6

Weighted mean: 2.2 minutes

Q3 : Combien de temps cela vous prend-il pour discuter avec une patiente d’un résultat anormal  d’ostéodensitométrie (expliquer le résultat, expliquer les bénéfices et risques de la médication, prescrire la médication)    

Prescribe medication:

1.1%-60sec: 0.6

1.1%-90 sec: 0.9

3.3%-120sec : 4

5.6%-180sec : 10

5.2%-240sec :12.5                                       

18.9%-300sec : 56.7

25.6%-480sec : 122.9

23.3%-600sec : 139.8

13.3%-900sec : 119.7

2.2%-1080sec : 23.8

Weighted mean: 8.2 minutes

Q4 : Combien de temps cela vous prend-il pour calculer le risque de fracture avec un(e) patient(e) et discuter des bénéfices et préjudices potentiels de la médication (en utilisant un outil d’aide à la décision)

SDM:                   

1.3% (1/79)-30sec : 0.4

1.3% (1/79)-60sec: 0.8

7.6%- (6/79)90sec : 6.8

2.5%-(2/79)120sec : 3                                            

10.1% (8/79)-180sec : 18.2

11.4% (9/79) – 240sec : 27.4

19% (15/79) -300sec : 57                              

19% (15/79) -480sec : 91.2

12.7% (10/79) -600sec : 76.2

11.4% (9/79) -900sec : 102.6

3.8% (3/79)-1080sec : 41

As 11 participants had never used a decision aid for this purpose (the denominator used was 79)

Weighted mean: 6.9 minutes

APPENDIX 3

Number of individuals by age

For ease of calculation, we considered there were no patients above 85 years old in the practice.

2.1 The number and proportion of women and men based on 2022 data.

In our sample practice, we have 300 patients 65-84 years of age (150 women and 150 men). Applying the above proportions, we would have the following number of patients in each age strata, by gender:

APPENDIX 4

Number of Screenings/- BMD-first strategy (not recommended by the Task Force)

In the 2010 Osteoporosis Canada guideline, recommendations on screening frequency were based on a risk assessment that includes BMD (FRAX or CAROC). They recommended treating high-risk individuals (risk > 20%) and re-screening with BMD after 1 to 3 years until BMD is stabilized and then every 3-5 years. In practice, patients identified as being at high risk through BMD can be re-screened with BMD annually (e.g., annual BMD is publicly funded through OHIP in Ontario for this population). For moderate-risk (risk 10 to 20%), rescreening was recommended every 1-3 years until BMD is stable, then at an interval of 3-5 years.  For individuals identified at low risk (risk < 10%), a repeat BMD screen was recommended in 3 years, then every 5-10 years if the individual remained at low risk. These recommendations use a risk threshold without any shared decision-making.

For purposes of our calculations, we used the following:

High risk = Rescreen at 2, 2, 3 then 5 years

Low to moderate risk = 2, 3, 3 then 5 years

Low risk = Rescreen at 3 then 5 years

Osteoporosis Canada also recommended screening women and men 50-64 if they had risk factors (they listed more than 10 – see the list on the first page ). Estimating how many individuals within a practice would have at least one of those risk factors (except for smoking) is not feasible.

Individuals 65-84 years

Each age group will repeat itself five times during 25 years of practice (i.e., you will have 5 groups of 65-69 years that will pass through; the second group of the 70-74 years old will be the first group of the 65-69 years and so on)

We used data from “Osteoporosis and related fractures in Canada: Report from the Canadian Chronic Disease Surveillance System 2020” to estimate the proportion of individuals considered high risk and thus considered treated. We consider this a conservative estimate as it likely underestimates the number of persons who will be screened if all are included.

High risk (HR)

Women

30.1% of women aged 65-69 years (53 X 0.301= 16 X 15 = 240)

36.2% of women aged 70-74 years (43 X 0.362= 16 X 7 = 112)

41.4% of women aged 75-79 years (33 X 0.414= 14 X 10 = 140)

45.6% of women aged 80-84 years (21 X 0.456= 10 X 11= 110)

Total : 602 BMD  AND 56 HR considered treated for 65+

Men

6% of men aged 65-69 years (56 X 0.060 = 3 X 15 = 45)

7.8% of men aged 70-74 years (43 X 0.078= 3 X 7 = 21)

10% of men aged 75-79 years (32 X 0.100= 3 X 10 = 30)

12.4% of men aged 80-84 years (19 X 0.124= 2 X 11 = 22)

Total :118 BMD  AND 11 HR considered treated for 65+

Low or moderate risk (no data available to separate these 2 groups) – considered “normal” (LR)

Women

69,9% of women aged 65-69 years (53 X 0.699 = 37 X 10 = 370)

63,8% of women aged 70-74 years (43 X 0.638= 27 X 10 = 270)

58,6% of women aged 75-79 years (33 X 0.586= 19 X 7 =133)

54,4% of women aged 80-84 years (21 X 0.544= 11 X 7 = 77)

Total 850 BMD

Men

94% of men aged 65-69 years    (56 X 0.94 = 53 X 10 = 530)

92,2% of men aged 70-74 years (43 X 0.922= 40 X 10 = 400)

90% of men aged 75-79 years    (32 X 0.90= 29 X 7 = 203)

87,6% of men aged 80-84 years (19 X 0.876= 17 X 7 = 119)

Total 1252 BMD

Total BMD for women: (602 (HR) + 850(LR)) (65-84 years) = 1452

Total BMD for men: (118  (HR)+ 1252 (LR)) (65-85 years) = 1370

TOTAL BMD: 2823

APPENDIX 5

Number of screenings – Risk assessment-first strategy (recommended by the Task Force)

Considering that repeating before 8 years does not appear beneficial

Considering no screening before 65 years (so it could be at 66 or 67)

Considering at a certain point you will have less than 20 years to go in your practice

Years 0-5 of your practice: number of risk assessment-first screenings

Women 65-69: 3

Women 70-74: 2

Women 75-79: 1.5

Women 80-84: 1

Years 6-10 of your practice (new women entering)

Women 65-69: 3

Years 11-15 of your practice (new women entering) – you only have 15 years left in your practice

Women 65-69: 2.5

Years 16-20 of your practice (new women entering) – you only have 10 years left in your practice

Women 65-69: 2

Years 21-25 of your practice (new women entering) – you only have 5 years left in your practice

Women 65-69: 1

The mean equals 2 assessments per women