Risk Factors
Risk-Factor Means to substitute for missing values
It is desirable to obtain values of all requested risk factors before calculating the ASSIGN score. However, it is possible to calculate a Provisional ASSIGN score using one or more mean values to substitute for missing values. These were obtained from the 2003 Scottish Health Survey so they are more recent than those obtained from the SHHEC study. The values are:
| Age (years) | Total Cholesterol | HDL Cholesterol | Systolic Blood Pressure | Cigarettes per day for smokers * | ||||
| Male | Female | Male | Female | Male | Female | Male | Female | |
| 30-39 | 5.50 | 5.11 | 1.35 | 1.58 | 128 | 116 | 13 | 14 |
| 40-49 | 5.77 | 5.64 | 1.37 | 1.64 | 130 | 121 | 17 | 16 |
| 50-59 | 6.02 | 6.29 | 1.40 | 1.71 | 133 | 131 | 20 | 14 |
| 60+ | 5.72 | 6.37 | 1.36 | 1.66 | 141 | 139 | 16 | 15 |
Smoking status should be known to calculate the ASSIGN score and should be requested if not available. If other factors are available, but not smoking, calculate a tentative score for a non-smoker and then for a smoker smoking an average number of cigarettes. Record both values to show the potential risk status, and then verify true status when you can.
After calculating a Provisional ASSIGN score the clinician may like to recalculate it substituting higher and lower values than the mean to see how robust it is, and how desirable to go back and obtain a real risk factor value to give a definitive score.
Risk-Factor Limits for ASSIGN. Definition of extreme and out-of-range values
For safety reasons it is undesirable to calculate an ASSIGN score in clinical practice using values which are so extreme as to be almost never encountered. The value may be erroneous; if not entered in error the measurement would need to be repeated, and if still true would be the subject of additional specific measures, not just incorporation into a risk score. Such values are queried when entered, as is the resulting score, which is calculated but flagged as questionable. Where risk factor data are out-of-range or nonsensical (eg 'Yes' for 'Number of cigarettes') the risk factor value is rejected and no score is calculated. These rules are slightly relaxed for the Research version of the score data entry format, allowing the user to conduct 'What if?' analysis. Extreme and out-of-range values were defined from the survey data of the Scottish Heart Health Extended Cohort (SHHEC), involving over 18000 people. For simplicity (unlike risk-factor means) the same values are used for extremes and ranges for different age and sex groups. Out-of-range values are those not occurring in this study. Extreme values are those occurring in less than 1% of participants.
The exception to the above rule is that ages beyond those of the original SHHEC cohort of 30-74 years are flagged because scoring involves extrapolation and the very young and very elderly are excluded although encountered in clinical practice. (See below)
| Risk Factor | Lower Bounds (inclusive) | Upper Bounds (inclusive) | ||
| Extreme Range | Usual Range | Extreme Range | ||
| Age (Years) | 25 | 30 | 74 | 90 |
| Cigarettes per day for smokers () | 0 | 0 | 40 | 100 |
| Systolic Blood Pressure (mmHg) | 80 | 100 | 200 | 250 |
| Total Cholesterol (mmol/l) | 2 | 3.5 | 9 | 12.5 |
| HDL Cholesterol (mmol/l) | 0.3 | 0.6 | 2.3 | 3.5 |